DaVinci PSP 03.22.00.04 Device Driver Features and Performance Guide

Document License

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Read This First

About This Manual

This document provides an overview and performance data for the device drivers which are part of the DaVinci Linux PSP package.

NOTE
For DA850 Spectrum Digital EVM, the performance numbers have been recorded with cpuidle driver enabled and with cpufreq governor set to userspace.

If You Need Assistance

For further information or to report any problems, contact http://community.ti.com/ or http://support.ti.com/

Trademarks

OMAP^TM and DaVinci^TM are trademarks of Texas Instruments, Incorporated. All other trademarks are the properties of their respective owners.

Support Overview

Boot Modes Supported

The following table provides information on the boot modes supported. Green color in the table below means that the particular boot mode is supported on the device.

DaVinci Supported Boot Modes

Boot Mode	DA850/OMAP-L138/AM18x	DA830/OMAP-L137/AM17x
SPI Flash
NAND Flash
NOR Flash
MMC/SD

NOTE
These are supported boot modes in PSP software, the actual hardware may support many more boot modes than shown here. Please refer to hardware documentation for list of all supported boot modes.

U-Boot Support

U-Boot is the defacto bootloader for Linux kernel on ARM. The following features of U-Boot are supported in this release:

U-Boot supported feature table

Feature	DA850 Spectrum Digital EVM	DA830 Spectrum Digital EVM	DA830-WiFi Spectrum Digital EVM
UART
Ethernet Download (TFTP)
MMC/SD
SPI Flash
NAND flash
NOR Flash

Device Driver List

The following table list the various device drivers supported and the platform/EVMs they are supported on. On detailed information on specific features or limitations of a pariticular driver, refer to the chapter catering to that driver in this document.

Peripheral Driver Support

Peripheral	Description	Linux driver type	DMA usage	Devices supported on
Audio (McASP)	Audio Record and Playback	ALSA SoC	EDMA3	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
EMAC	Ethernet Network driver	Netdev	EMAC Internal DMA	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
USB MSC Host	USB Mass Storage Class Host Driver	Block	USB Internal DMA	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVMI
USB HID Host	USB Human Interface Device Host Driver	Input driver	USB Internal DMA	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
USB MUSB HCD	MUSB Host controller driver	USB HCD	USB Internal DMA	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
USB OHCI HCD	OHCI Host controller driver	USB HCD	USB Internal DMA	DA830 Spectrum Digital EVM, DA850 Spectrum Digital EVM
NAND Flash	Flash storage system	MTD Character and Block	Not Supported	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
NOR Flash	Flash storage system	MTD Character and Block	Not Supported	DA850 Spectrum Digital EVM
GLCD	Graphical LCD driver	Frame Buffer	LCDC Internal DMA	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
CLCD	Character LCD driver	Parallel port based driver	None	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
SPI Flash	Flash storage system	MTD Character and Block	EDMA3	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
MMC/SD	Interface to MultiMedia Secure Digital cards	Block	EDMA3	DA830 Spectrum Digital EVM, DA850 Spectrum Digital EVM
UART	Serial Communication Interface	Character	Not Supported	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
I2C	Inter-IC Communication	Character	Not Supported	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
RTC	Real-time clock	Character	None	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
Watchdog	Watchdog Timer	Miscellaneous	None	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
SPI	Serial Peripheral Interface	Character	EDMA3	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
Power Management	Linux drivers cpuidle, cpufreq and Suspend-to-RAM	Misc	None	DA850 Spectrum Digital EVM
Touchscreen	Drivers for TPS65070	Input driver	None	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
eCAP	PWM Capture and Generation	Miscellaneous	None	DA830 Spectrum Digital EVM, DA830-WiFi Spectrum Digital EVM, DA850 Spectrum Digital EVM
eHRPWM	PWM generation	Miscellaneous	None	DA850 Spectrum Digital EVM

Power Management measurements

Suspend/Resume timings

It takes 544.737 msecs to suspend and 574.583 msecs to resume with default kernel. Please find below log for individual module timings, captured by appending initcall_debug to kernel bootargs. Resume time is more than expected because there is a delay to resume device safely.

root@arago:~# rtcwake -s 2 -d /dev/rtc0 -m mem
wakeup from "mem" at Sat Jan  1 00:09:36 2000
PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.02 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
calling  soc-audio.0+ @ 1076, parent: platform
call soc-audio.0+ returned 0 after 1346 usecs
calling  snd-soc-dummy+ @ 1076, parent: platform
call snd-soc-dummy+ returned 0 after 4 usecs
calling  rtc0+ @ 1076, parent: omap_rtc
call rtc0+ returned 0 after 26 usecs
calling  input0+ @ 1076, parent: 1-0025
call input0+ returned 0 after 5 usecs
calling  usb1+ @ 526, parent: ohci.0
calling  davinci_mdio-0:00+ @ 1076, parent: davinci_mdio.0
call davinci_mdio-0:00+ returned 0 after 140 usecs
call usb1+ returned 0 after 96 usecs
calling  mtd3ro+ @ 1076, parent: spi1.0
call mtd3ro+ returned 0 after 5 usecs
calling  mtd3+ @ 1076, parent: spi1.0
call mtd3+ returned 0 after 3 usecs
calling  mtd2ro+ @ 1076, parent: spi1.0
call mtd2ro+ returned 0 after 3 usecs
calling  mtd2+ @ 1076, parent: spi1.0
call mtd2+ returned 0 after 4 usecs
calling  mtd1ro+ @ 1076, parent: spi1.0
call mtd1ro+ returned 0 after 4 usecs
calling  mtd1+ @ 1076, parent: spi1.0
call mtd1+ returned 0 after 3 usecs
calling  mtd0ro+ @ 1076, parent: spi1.0
call mtd0ro+ returned 0 after 4 usecs
calling  mtd0+ @ 1076, parent: spi1.0
call mtd0+ returned 0 after 3 usecs
calling  spi1.0+ @ 1076, parent: spi1
call spi1.0+ returned 0 after 4 usecs
calling  serial8250+ @ 1076, parent: platform
call serial8250+ returned 0 after 5 usecs
calling  alarmtimer+ @ 1076, parent: platform
call alarmtimer+ returned 0 after 12 usecs
calling  davinci_emac.1+ @ 1076, parent: platform
call davinci_emac.1+ returned 0 after 2996 usecs
calling  davinci_mdio.0+ @ 1076, parent: platform
call davinci_mdio.0+ returned 0 after 30 usecs
calling  1-0021+ @ 1076, parent: i2c-1
call 1-0021+ returned 0 after 6 usecs
calling  1-0064+ @ 1076, parent: i2c-1
call 1-0064+ returned 0 after 4 usecs
calling  1-0020+ @ 1076, parent: i2c-1
call 1-0020+ returned 0 after 3 usecs
calling  1-0018+ @ 1076, parent: i2c-1
call 1-0018+ returned 0 after 3 usecs
calling  1-0048+ @ 1076, parent: i2c-1
call 1-0048+ returned 0 after 3 usecs
calling  1-0025+ @ 1076, parent: i2c-1
call 1-0025+ returned 0 after 5 usecs
calling  i2c-1+ @ 1076, parent: i2c-gpio.1
call i2c-1+ returned 0 after 3 usecs
calling  ahci+ @ 1076, parent: platform
call ahci+ returned 0 after 2 usecs
calling  ohci.0+ @ 1076, parent: platform
call ohci.0+ returned 0 after 38 usecs
calling  spi_davinci.1+ @ 1076, parent: platform
call spi_davinci.1+ returned 0 after 24 usecs
calling  pm-davinci+ @ 1076, parent: platform
call pm-davinci+ returned 0 after 3 usecs
calling  cpuidle-davinci.0+ @ 1076, parent: platform
call cpuidle-davinci.0+ returned 0 after 3 usecs
calling  cpufreq-davinci+ @ 1076, parent: platform
call cpufreq-davinci+ returned 0 after 2 usecs
calling  omap_rtc+ @ 1076, parent: platform
call omap_rtc+ returned 0 after 16 usecs
calling  da8xx_lcdc.0+ @ 1076, parent: platform
call da8xx_lcdc.0+ returned 0 after 195354 usecs
calling  davinci-mcbsp.1+ @ 1076, parent: platform
call davinci-mcbsp.1+ returned 0 after 4 usecs
calling  davinci-pcm-audio+ @ 1076, parent: platform
call davinci-pcm-audio+ returned 0 after 3 usecs
calling  serial8250.0+ @ 1076, parent: platform
call serial8250.0+ returned 0 after 144 usecs
calling  davinci_mmc.0+ @ 1076, parent: platform
call davinci_mmc.0+ returned 0 after 1057 usecs
calling  davinci_mmc.1+ @ 1076, parent: platform
call davinci_mmc.1+ returned 0 after 1045 usecs
calling  watchdog+ @ 1076, parent: platform
call watchdog+ returned 0 after 3 usecs
calling  i2c-gpio.1+ @ 1076, parent: platform
call i2c-gpio.1+ returned 0 after 3 usecs
calling  edma+ @ 1076, parent: platform
call edma+ returned 0 after 3 usecs
calling  reg-dummy+ @ 1076, parent: platform
call reg-dummy+ returned 0 after 4 usecs
PM: suspend of devices complete after 544.737 msecs
PM: late suspend of devices complete after 1.158 msecs
PM: Calling irq_gc_suspend+0x0/0x50
PM: Calling timekeeping_suspend+0x0/0x13c
PM: Calling leds_suspend+0x0/0x28
PM: Calling cpufreq_bp_suspend+0x0/0x64
PM: Calling cpu_pm_suspend+0x0/0x20
PM: Calling cpu_pm_resume+0x0/0x18
PM: Calling cpufreq_bp_resume+0x0/0x68
PM: Calling leds_resume+0x0/0x24
PM: Calling timekeeping_resume+0x0/0x124
PM: Calling irq_gc_resume+0x0/0x4c
PM: Calling irq_pm_syscore_resume+0x0/0x18
PM: early resume of devices complete after 0.412 msecs
calling  reg-dummy+ @ 1076, parent: platform
call reg-dummy+ returned 0 after 5 usecs
calling  edma+ @ 1076, parent: platform
call edma+ returned 0 after 5 usecs
calling  i2c-gpio.1+ @ 1076, parent: platform
call i2c-gpio.1+ returned 0 after 3 usecs
calling  watchdog+ @ 1076, parent: platform
call watchdog+ returned 0 after 3 usecs
calling  davinci_mmc.1+ @ 1076, parent: platform
call davinci_mmc.1+ returned 0 after 46 usecs
calling  davinci_mmc.0+ @ 1076, parent: platform
call davinci_mmc.0+ returned 0 after 37 usecs
calling  serial8250.0+ @ 1076, parent: platform
call serial8250.0+ returned 0 after 254 usecs
calling  davinci-pcm-audio+ @ 1076, parent: platform
call davinci-pcm-audio+ returned 0 after 3 usecs
calling  davinci-mcbsp.1+ @ 1076, parent: platform
call davinci-mcbsp.1+ returned 0 after 3 usecs
calling  da8xx_lcdc.0+ @ 1076, parent: platform
call da8xx_lcdc.0+ returned 0 after 202839 usecs
calling  omap_rtc+ @ 1076, parent: platform
call omap_rtc+ returned 0 after 17 usecs
calling  cpufreq-davinci+ @ 1076, parent: platform
call cpufreq-davinci+ returned 0 after 4 usecs
calling  cpuidle-davinci.0+ @ 1076, parent: platform
call cpuidle-davinci.0+ returned 0 after 3 usecs
calling  pm-davinci+ @ 1076, parent: platform
call pm-davinci+ returned 0 after 3 usecs
calling  spi_davinci.1+ @ 1076, parent: platform
call spi_davinci.1+ returned 0 after 29 usecs
calling  ohci.0+ @ 1076, parent: platform
Waiting for USB PHY clock good...
call ohci.0+ returned 0 after 3111 usecs
calling  usb1+ @ 526, parent: ohci.0
calling  ahci+ @ 1076, parent: platform
call ahci+ returned 0 after 3 usecs
calling  i2c-1+ @ 1076, parent: i2c-gpio.1
call i2c-1+ returned 0 after 3 usecs
calling  1-0025+ @ 1076, parent: i2c-1
call 1-0025+ returned 0 after 3 usecs
calling  1-0048+ @ 1076, parent: i2c-1
call 1-0048+ returned 0 after 3 usecs
calling  1-0018+ @ 1076, parent: i2c-1
call 1-0018+ returned 0 after 3 usecs
calling  1-0020+ @ 1076, parent: i2c-1
call 1-0020+ returned 0 after 2 usecs
calling  1-0064+ @ 1076, parent: i2c-1
call 1-0064+ returned 0 after 7 usecs
calling  1-0021+ @ 1076, parent: i2c-1
call 1-0021+ returned 0 after 3 usecs
calling  davinci_mdio.0+ @ 1076, parent: platform
call davinci_mdio.0+ returned 0 after 29 usecs
calling  davinci_emac.1+ @ 1076, parent: platform
davinci_mdio davinci_mdio.0: resetting idled controller
net eth0: attached PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=davinci_mdio-0:00, id=7c0f1)
call davinci_emac.1+ returned 0 after 16873 usecs
calling  alarmtimer+ @ 1076, parent: platform
call alarmtimer+ returned 0 after 3 usecs
call usb1+ returned 0 after 98570 usecs
calling  serial8250+ @ 1076, parent: platform
call serial8250+ returned 0 after 7 usecs
calling  spi1.0+ @ 1076, parent: spi1
call spi1.0+ returned 0 after 5 usecs
calling  mtd0+ @ 1076, parent: spi1.0
call mtd0+ returned 0 after 3 usecs
calling  mtd0ro+ @ 1076, parent: spi1.0
call mtd0ro+ returned 0 after 2 usecs
calling  mtd1+ @ 1076, parent: spi1.0
call mtd1+ returned 0 after 3 usecs
calling  mtd1ro+ @ 1076, parent: spi1.0
call mtd1ro+ returned 0 after 3 usecs
calling  mtd2+ @ 1076, parent: spi1.0
call mtd2+ returned 0 after 3 usecs
calling  mtd2ro+ @ 1076, parent: spi1.0
call mtd2ro+ returned 0 after 1 usecs
calling  mtd3+ @ 1076, parent: spi1.0
call mtd3+ returned 0 after 3 usecs
calling  mtd3ro+ @ 1076, parent: spi1.0
call mtd3ro+ returned 0 after 2 usecs
calling  davinci_mdio-0:00+ @ 1076, parent: davinci_mdio.0
call davinci_mdio-0:00+ returned 0 after 108 usecs
calling  input0+ @ 1076, parent: 1-0025
call input0+ returned 0 after 270 usecs
calling  rtc0+ @ 1076, parent: omap_rtc
call rtc0+ returned 0 after 66 usecs
calling  snd-soc-dummy+ @ 1076, parent: platform
call snd-soc-dummy+ returned 0 after 4 usecs
calling  soc-audio.0+ @ 1076, parent: platform
call soc-audio.0+ returned 0 after 6922 usecs
PM: resume of devices complete after 574.583 msecs
Restarting tasks ... done.
PHY: davinci_mdio-0:00 - Link is Up - 100/Full

ALSA SoC Audio Driver

Abstract

This chapter provides details on ALSA SoC audio driver along with CPU load numbers.

Introduction

DaVinci Audio driver complies to the Advanced Linux Sound Architecture (ALSA) System on Chip (SoC) framework (ASoC).

The ASoC framework splits an embedded audio system into three components:

• Codec driver: The codec driver is generic and hardware independent code that configures the audio codec to provide audio capture and playback. It should contain no code that is specific to the target platform or machine.
• Platform driver: The platform driver can be divided into audio DMA and SoC Digital Audio Interface (DAI) configuration and control. The platform driver only targets the SoC CPU and must have no board specific code.
• Machine driver: The ASoC machine (or board) driver is the code that glues together the platform and codec drivers. It can contain codec and platform specific code. It registers the audio subsystem with the kernel as a platform device.

Following architecture diagram shows all the components and the interactions among them:

Driver Features

1. The driver supports the following features:
2. Supports AIC3106 audio codec in ALSA SoC framework.
3. Multiple sample rate support (8 KHz, 44.1 KHz and 48 KHz commonly used) for both capture and playback.
4. Supports audio in stereo mode.
5. Supports simultaneous playback and record (full-duplex mode).
6. Start, stop, pause and resume feature.
7. Supports mixer interface for audio codecs.

Features Not Supported

1. Does NOT support OSS based applications using OSS emulation layer.
2. Driver will not work if built as module.

Constraints

• By default, codec is configured in master mode and McASP is used as slave. Testing of the audio sub-system is done in this configuration only.
• Configuration of playback and capture streams in different sampling rates is not supported.
• Pin 2 of Boot switch should be "ON" on DA850 Spectrum Digital EVM to use playback capture.

Supported System Calls

Refer ALSA project - the C library reference [1] for API calls.

Performance and Benchmarks

The performance numbers were captured using the following:

• Word length in bits = 16
• Number of channels per sample = 2

Audio Write Performance

Sampling Rate (in Hz)	CPU Load (in %)
	DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
8000	1	1	1	1	1	1
44100	8	7	7	8	7	8
48000	8	7	7	8	7	8

Audio Read Performance

Sampling Rate (in Hz)	CPU Load (in %)
	DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
8000	3	2	3	2	3	2
44100	8	7	8	7	8	7
48000	8	7	8	7	8	7

Ethernet Driver

Abstract

This chapter provides details on Ethernet driver along with throughput and CPU load numbers.

Introduction

The Ethernet driver supports the Linux netdev interface.

Driver Features

The driver supports the following features:

1. 10/100 Mbps mode of operation.
2. Auto negotiation.
3. Support for multicast and broadcast frames.
4. Promiscuous mode of operation.
5. Full duplex and half duplex mode of operation.
6. Linux NAPI support
7. Support for MII and RMII interfaces to PHY

Supported System Calls

Supports the socket() and related system calls in accordance with Linux architecture.

Performance and Benchmarks

Ethernet 100Mbps Mode Performance

TCP Window Size(in KBytes)	Interval (in Seconds)	Transfer Rate MII PHY (in Mbps)						Transfer Rate RMII PHY (in Mbps)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
16	60	41.3	47.4	39.2	45.4	40.1	44.2	43.4	51.7	NA	NA	NA	NA
32	60	46.9	52.3	44.8	51.2	43.4	51.4	48.3	55.4	NA	NA	NA	NA
64	60	44.2	54.7	41.2	52.7	40.2	51.7	48.1	55.8	NA	NA	NA	NA
128	60	45.4	53.6	44.3	51.2	44.2	50.2	48.9	55.9	NA	NA	NA	NA

NOTE
RMII PHY support is available only on DA850/OMAPL138/AM18x SDI.
CPU load during the performance test is 90%

The performance numbers were captured using the iperf tool. Usage details are mentioned below:

• Server side command switch : "-s"
• Client side command : "-c <server ip> -w <window size> -d -t60". This starts bi-directional traffic to the server for a duration of 60 seconds.
• Iperf tool is run on the DUT1 in server mode and on DUT2 in client mode. Version 2.0.4 is used on both sides.
• Data captured here is for "iperf" in client mode.
• Cross cable is used to measure performance.
• Speed is set to 100Mbps

Graphical LCD (GLCD) Driver (DA850/OMAP-L138/AM18x)

Abstract

This chapter describes the GLCD driver architecture, driver features and performance numbers (throughput and CPU load).

Introduction

GLCD driver is based on Fbdev framework.

Driver Features

1. Supports QVGA display through Fbdev framework.
2. Supports display of RGB565 images.
3. Supports getting and setting the variable screen information.
4. Supports retrieving the fixed screen information.

Features Not Supported

1. Brightness and color control ioctls not supported.

Supported System Calls

open(), close(), read(), mmap(), ioctl()

NAND Driver

Abstract

This chapter describes the NAND flash driver architecture, driver features and performance numbers (throughput and CPU load).

Introduction

The NAND driver is implemented as a character and block driver, compliant with the Linux MTD subsystem interface. It supports various NAND Flash chips (see file drivers/mtd/nand/nand_ids.h in Linux kernel sources) The NAND driver creates the device nodes for user space access (/dev/mtdblock0, /dev/mtdblock1, /dev/mtd0,/dev/mtd1 and so on.).

This figure illustrates the stack diagram of NAND flash driver in Linux.

Driver Features

The driver supports the following features:

1. JFFS2 and UBIFS file system support
2. Supports Read, Write and Erase
3. Bad Block Management
4. Polled mode of transfer
5. Small Block (512 bytes), Big Block (2K & 4K bytes), SLC NAND

Features Not Supported

1. flash_eraseall with -j option fails. Please use without -j option

Supported System Calls

Supports the system call support proivided by Linux MTD interface viz. open(), close(), read(), write(), ioctl()

Performance Benchmarks

NAND Write performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	0.2	0.3	0.2	0.3	0.2	0.3	99	99	98	99	98	99
256	100	0.2	0.3	0.2	0.3	0.2	0.3	99	99	98	98	99	99
512	100	0.2	0.3	0.2	0.3	0.2	0.3	98	99	99	98	98	98
1024	100	0.2	0.3	0.2	0.3	0.2	0.3	99	98	99	98	99	99
5120	100	0.2	0.3	0.2	0.3	0.2	0.3	98	99	99	99	99	99

NAND Read performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	2.5	3.2	2.4	3.1	2.4	3.2	98	99	99	98	99	98
256	100	2.5	3.2	2.4	3.1	2.4	3.1	98	99	98	99	98	99
512	100	2.5	3.2	2.4	3.1	2.4	3.1	98	99	98	99	98	99
1024	100	2.5	3.2	2.4	3.1	2.4	3.1	98	99	98	99	98	99
5120	100	2.5	3.2	2.4	3.1	2.4	3.1	98	99	98	99	98	99

The performance numbers are captured using the following:

1. NAND PART Number: Micron MT29F4G08AAC
2. File System = JFFS2
3. NAND partition was mounted with async option.

NOR flash Driver

Abstract

This chapter describes the NOR flash driver architecture, driver features and performance numbers (throughput and CPU load).

Introduction

The NOR flash driver is implemented as a character and block device driver, compliant with the Linux MTD subsystem architecture. It supports various CFI compliant NOR flash chips. The NOR flash driver creates the device nodes for user space access (/dev/mtdblock0, /dev/mtdblock1, /dev/mtd0,/dev/mtd1 and so on.).

Driver Features

The driver supports the following features:

1. JFFS2 file system support
2. Supports Read, Write and Erase
3. Polled mode of transfer

Supported System Calls

Supports the system call support proivided by Linux MTD interface viz. open(), close(), read(), write(), ioctl()

Performance Benchmarks

NOR Write performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	3	0.1	0.1	NA	NA	NA	NA	78	75	NA	NA	NA	NA
256	3	0.1	0.1	NA	NA	NA	NA	78	74	NA	NA	NA	NA
512	3	0.1	0.1	NA	NA	NA	NA	81	75	NA	NA	NA	NA
1024	3	0.1	0.1	NA	NA	NA	NA	81	74	NA	NA	NA	NA

NOR Read performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	3	0.1	0.1	NA	NA	NA	NA	98	99	NA	NA	NA	NA
256	3	0.1	0.1	NA	NA	NA	NA	98	99	NA	NA	NA	NA
512	3	0.1	0.1	NA	NA	NA	NA	98	99	NA	NA	NA	NA
1024	3	0.1	0.1	NA	NA	NA	NA	98	99	NA	NA	NA	NA

NOTE
NOR driver support is available only on DA850/OMAPL138/AM18x.

The performance numbers are captured using the following:

1. NOR PART Number: Intel PC28F640P30T85
2. File System = JFFS2
3. NOR partition was mounted with async option.

SPI Flash Driver

Abstract

This chapter describes the SPI flash driver architecture, driver features and performance numbers (throughput and CPU load).

Introduction

SPI Flash driver is implemented as block driver and compliant with standard MTD driver. It supports various flash devices. The SPI driver creates device node for user space access (example, /dev/mtd1).

Driver Features

• DMA and PIO modes are supported.

Supported System Calls

Supports the system call support proivided by MTD interface viz. open(), close(), read(), write(), ioctl()

Performance Benchmarks

Performance numbers will be provided later

MMC/SD Driver

Abstract

This chapter provides details on MMC/SD driver along with throughput and CPU load numbers.

Introduction

The MMC controller provides an interface to external MMC cards that follow the MMC specification v4.0. The MMC driver is implemented as a block driver. Block device nodes(such as /dev/mmcblockp1, /dev/mmcblockp2) are created for user space access.

Driver Features

The driver supports the following features:

1. MMC/SD native protocol command/response set
2. Single/multiple block data transfers
3. Linux file system and generic MMC layer abstract details of block devices (MMC)
4. High-speed (SDv1.1) and High Capacity (SDv2.0) cards
5. Support for 1/4 bit modes
6. Support for card detect and Write protect features
7. DMA and polled mode for data transfer operations

Features Not Supported

1. Support for 8-bit mode of operation.
2. SDIO - WLAN support
3. SPI mode of operation

Constraints

1. MMC/SD cards should not be removed when the mount operation is in progress. If done so, data integrity cannot be guaranteed.

Supported System Calls

open(),close(),read(),write()

Performance and Benchmarks

IMPORTANT
The performance numbers can be severely affected if the media is mounted in sync mode. Hot plug scripts in the filesystem mount removable media in sync mode to ensure data integrity. For performance sensitive applications, umount the auto-mounted filesystem and re-mount in async mode.

The performance numbers were captured using class 10 SDHC Card (SanDisk, 8GB)

Performance using EXT2 file system

Write performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	7.5	8.3	7.3	8.1	NA	NA	74	65	77	66	NA	NA
256	100	7.3	8.4	7.4	7.9	NA	NA	77	67	75	66	NA	NA
512	100	8.1	8.2	7.9	8.1	NA	NA	77	69	76	69	NA	NA
1024	100	7.5	8.2	7.4	8.1	NA	NA	77	67	75	66	NA	NA
5120	100	7.5	8.1	7.2	7.9	NA	NA	77	66	76	65	NA	NA

Read performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	14.1	15.2	13.9	14.9	NA	NA	42	37	43	38	NA	NA
256	100	14.3	15.2	13.9	14.8	NA	NA	43	37	42	38	NA	NA
512	100	14.1	15.1	13.8	14.7	NA	NA	41	36	40	38	NA	NA
1024	100	14.3	15.1	13.9	14.6	NA	NA	41	37	40	38	NA	NA
5120	100	14.1	15.2	13.8	14.7	NA	NA	42	39	44	38	NA	NA

Performance using VFAT file system

Write performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	6.2	7.1	5.9	6.8	NA	NA	66	59	65	57	NA	NA
256	100	6.3	7.1	6.1	6.9	NA	NA	66	57	65	56	NA	NA
512	100	6.4	7.2	6.2	6.9	NA	NA	66	58	65	57	NA	NA
1024	100	6.3	7.1	6.1	6.8	NA	NA	66	57	65	55	NA	NA
5120	100	6.4	7.1	6.2	6.9	NA	NA	66	58	65	57	NA	NA

Read performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	13.7	14.5	13.4	14.1	NA	NA	41	40	40	42	NA	NA
256	100	13.7	14.3	13.3	14.1	NA	NA	42	39	41	38	NA	NA
512	100	13.3	14.2	13.1	13.9	NA	NA	44	38	45	39	NA	NA
1024	100	13.9	14.5	13.5	14.3	NA	NA	44	38	42	39	NA	NA
5120	100	13.8	14.4	13.5	14.3	NA	NA	46	40	45	41	NA	NA

UART Driver

Abstract

This chapter provides details on UART driver.

Introduction

The UART driver is implemented as a serial driver, and can be accessed from user space as /dev/ttyS2.

Driver Features

The driver supports the following features:

1. Only UART2 is physically available on EVM board

Supported System Calls

open(),close(),read(),write(),ioctl()

Supported IOCTLs

Constant	Description
TIOCGSERIAL	Gets device parameters from the UART (example, port type, port num, baud rate, base divisor, and so on.
TIOCSSERIAL	Sets UART device parameters (example, port type, port num, baud rate, base divisor, and so on)

I2C Driver

Abstract

This chapter provides details on I2C driver.

Introduction

The I2C peripheral is compliant with the Philips Semiconductor I2C-bus specification version 2.1. The I2C driver is implemented as a serial driver. The I2C driver can be accessed from the user space as /dev/i2c/0.

Driver Features

The driver supports the following features:

1. 7-bit addressing mode
2. Fast mode
3. Interrupt mode

Features Not Supported

1. 7-bit and 10-bit addressing combined format is not supported
2. DMA mode is not supported

Supported System Calls

open(),close(),read(),write(),ioctl()

Supported IOCTLs

Constant	Description
I2C_SLAVE_FORCE	Changes slave address. Slave address is 7 or 10 bits. This changes the address, even if it is already considered.
I2C_TENBIT	7- or 10-bit address. (Value = 0 for 7 bits; value != 0 for 10 bits.)
I2C_FUNCS	Gets the adapter functionality
I2C_RDWR	Combined R/W transfer (one stop only)

EDMA Driver

Abstract

This chapter provides details on EDMA driver along with throughput and CPU load numbers.

Introduction

The EDMA controller handles all data transfers between the level-two (L2) cache/memory controller and the device peripherals. On DA850/OMAPL138 EDMA has 2 CC instances where as the other SoCs have one instance. Each EDMA instance supports up to 32-dma channels and 8 QDMA channels. The EDMA consists of a scalable Parameter RAM (PaRAM) that supports flexible ping-pong, circular buffering, channel-chaining, auto-reloading, and memory protection. The EDMA allows movement of data to/from any addressable memory spaces, including internal memory (L2 SRAM), peripherals, and external memory.

The EDMA driver exposes only the kernel level API's. This driver is used as a utility by other drivers for data transfer.

Driver Features

The driver supports the following features:

1. Request and Free DMA channel
2. Programs DMA channel
3. Start and Synchronize with DMA transfers
4. Provides DMA transaction completion callback to applications
5. Multiple instances of EDMA driver on a single processor

Features Not Supported

1. QDMA is not supported.
2. Reservation of resources (channels and PaRAMs) for usage from DSP is not supported.

Watchdog(WDT) Driver

Abstract

This chapter provides details on Watchdog timer driver.

Introduction

DaVinci SoCs have a 64-bit watchdog timer which can be used to reset the hardware in case of a software fault. Once the /dev/watchdog is opened, it will reboot the system unless a user space daemon resets the timer at regular intervals within a certain timeout period. The WDT driver is registered as a misc device. Default timeout of this driver is 60 seconds.

Driver Features

The driver supports the following features:

1. Supports IOCTLs to set/get the timeout value, ping the watchdog & query the watchdog structure info.
2. Driver can be built as a loadable module and inserted dynamically.

Constraints

1. Once /dev/watchdog is opened, closing it doesn't disable the watchdog

Supported System Calls

open(), close(), write(), read()

Supported IOCTLs

Constant	Description
WDIOC_GETSUPPORT	This ioctl returns "struct watchdog_info", which tells what the device can do
WDIO_KEEPALIVE	This ioctl can be used to notify the watchdog timer that the user space application is alive
WDIO_SETTIMEOUT	Watchdog timeout or margin can be dynamically changed using this ioctl
WDIO_GETTIMEOUT	This ioctl returns the present watchdog timeout period in seconds

USB Driver

Abstract

This chapter provides details on OHCI and MUSB drivers along with throughput and CPU load numbers.

This chapter describes the USB (EHCI and MUSB) driver architecture, features supported/not supported, constraints and performance numbers.

OHCI Controller

Driver Features

The driver supports the following features

1. Human Interface Class (HID)
2. Mass Storage Class (MSC)
3. Hub Class
4. USB Video Class (UVC)
5. USB Audio Class (UAC)

Features Not Supported

All other classes not mentioned in the "Supported Features" section.

MUSB OTG controller

Description

The MUSB driver is implemented on top of Mentor OTG IP version 1.8 which supports all the speeds (High, Full and Low (host mode only)). On DA850/OMAP-L138, MUSB uses CPPI 4.1 DMA for all the transfers on other devices CPPI 3.0 DMA is used.

Driver Features

The driver supports the following features

Host Mode

1. Human Interface Class (HID)
2. Mass Storage Class (MSC)
3. Hub Class
4. USB Video Class (UVC)
5. USB Audio Class (UAC)

Gadget mode

1. Mass Storage Class (MSC)
2. USB Networking - RNDIS/CDC

Features Not Supported

• OTG
• Modular support for host/device mode.

USB Mass Storage Class Host Driver

Driver Features

The driver supports the following feature

1. DMA mode
2. PIO mode

Supported System Calls

open(), close(), read(), write(), ioctl()

Performance Benchmarks

IMPORTANT
For Mass-storage applications, the performance numbers can be severely affected if the media is mounted in sync mode. Hot plug scripts in the filesystem mount removable media in sync mode to ensure data integrity. For performance sensitive applications, umount the auto-mounted filesystem and re-mount in async mode.

USB MSC (MUSB) Host mode DMA EXT2 File System Performance

USB-MSC MUSB Host-DMA-Write Performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	2.2	2.5	2.2	2.4	2.2	2.4	25	19	24	18	24	19
512	100	2.2	2.4	2.2	2.3	2.3	2.4	29	17	28	18	27	18
1024	100	2.4	2.5	2.3	2.5	2.3	2.5	20	17	19	18	19	17
5120	100	2.6	2.7	2.3	2.5	2.2	2.5	26	14	27	15	27	17

USB-MSC MUSB Host-DMA-Read Performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	8.2	8.4	8.1	8.3	8.1	8.2	59	47	58	46	57	45
512	100	8.1	8.7	7.9	8.5	7.8	8.3	61	47	60	45	59	44
1024	100	8.1	8.4	8.2	8.4	8.1	8.5	64	47	66	48	65	49
5120	100	7.9	8.7	8.1	8.4	7.9	8.3	65	47	66	48	64	47

The performance numbers are captured using the following.

1. Using 2GB SD card via card reader

USB MSC (MUSB) Host mode DMA VFAT File System Performance

USB-MSC MUSB Host-DMA-Write Performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	3.6	3.9	3.5	3.8	3.4	3.7	41	33	42	34	43	35
512	100	3.6	4.1	3.5	4.2	3.3	4.1	40	33	41	32	41	33
1024	100	3.7	4.1	3.5	4.1	3.5	4.1	41	33	42	34	43	33
5120	100	3.6	3.9	3.5	3.8	3.4	3.7	39	32	40	33	41	33

USB-MSC MUSB Host-DMA-Read Performance values

Buffer Size (in KBytes)	Total Bytes Transferred (in MBytes)	Transfer Rate (in MBytes/sec)						CPU Load (in %)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
100	100	8.1	8.7	7.9	8.3	7.8	8.4	66	56	67	57	65	56
512	100	8.4	8.7	8.3	8.6	8.2	8.6	65	52	64	53	64	52
1024	100	8.1	8.5	8.1	8.4	8.1	8.3	64	49	63	50	62	51
5120	100	8.1	8.2	7.9	8.2	7.8	8.3	65	53	66	54	67	54

The performance numbers are captured using the following.

1. SD card via USB card reader.
2. File format: VFAT
   

USB Mass Storage Class Slave Driver

Description

This figure illustrates the stack diagram of the system with USB File Storage Gadget driver

Driver Features

The driver supports the following feature

1. DMA mode
2. PIO mode
3. File backed storage driver was tested with SD media as the storage medium

Features Not Supported

• Modular support

Performance Benchmarks

USB Slave-DMA Performance

USB Slave-DMA-Write Performance values

Bytes Transferred (MB)	Number of files transferred	Total Bytes transferred (MB)
			Data Rate (MB/sec)
			DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
			300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
51	1	51	10.9	11.8	10.5	11.4	10.4	11.4

USB Slave-DMA-Read Performance values

Bytes Transferred (MB)	Number of files transferred	Total Bytes transferred (MB)
			Data Rate (MB/sec)
			DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
			300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
51	1	51	12.2	14.9	11.9	13.8	11.6	13.5

The performance numbers are captured in DMA Mode using a file inside /dev/shm as storage gadget media exposing as removable media to Windows-XP over USB. The storage media is formatted using the FAT32 on Windows-XP.
Storage gadget media file is created using the command:

# dd if=/dev/zero of=/dev/shm/50M bs=1M count=50"

Insert the USB mass storage gadget with /dev/shm/50M as the backing storage:

# insmod g_mass_storage.ko file=/dev/shm/50M 

The performance numbers are captured using script on window

@echo Start time: %time%
copy f:\50M d:\
@echo Stop time: %time%

@echo Start time: %time%
copy d:\50M f:\50M
@echo Stop time: %time%

USB CDC/RNDIS Slave Driver

Description

The CDC RNDIS gadget driver that is used to send standard Ethernet frames using USB. The driver will create an Ethernet device by the name usb0.

Driver Features

The driver supports the following feature

1. DMA mode
2. PIO mode
3. 10/100 Mbps speed.

Supported System Calls

open(), close(), read(), write(), ioctl()

Performance Benchmarks

Performance benchmarks were collected using the Iperf tool and default options were used to collect the throughput numbers.

DA850/OMAP-L138

USB CDC-DMA Performance

USB CDC-DMA Performance values - Client

TCP Window Size(in KBytes)	Interval (in Seconds)	Bandwidth (Mbits/Sec)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
16	10	22.3	39.8	21.9	39.5	21.8	39.6
32	10	22.8	39.9	21.8	39.5	21.6	39.6
64	10	22.5	39.5	21.8	39.5	21.6	39.6
128	10	21.2	39.3	21.3	39.3	21.5	39.4

USB RNDIS-DMA Performance

USB RNDIS-DMA Performance values - Client

TCP Window Size(in KBytes)	Interval (in Seconds)	Bandwidth (Mbits/Sec)
		DA850 Spectrum Digital EVM		DA830 Spectrum Digital EVM		DA830-WiFi Spectrum Digital EVM
		300 MHz	456 MHz	300 MHz	456 MHz	300 MHz	456 MHz
16	10	23.3	26.6	22.3	26.5	22.3	26.4
32	10	22.8	28.1	22.7	28.1	22.4	27.9
64	10	21.1	25.7	20.9	24.9	20.8	24.6
128	10	20.9	25.1	20.5	24.9	20.4	24.8

USB Human Interface Device (HID) Driver

Description

The event sub system creates /dev/input/event* devices with the help of mdev.

Driver Features

The driver supports the following feature

1. DMA mode
2. PIO mode
3. USB Mouse and Keyboards that conform to the USB HID specifications

USB Isochronous Driver

Description

USB camera, speaker and mic uses isochronouse transfers. USB Video Class (UVC) is used by most of the USB cameras to capture image.

Driver Features

The driver supports the following feature

1. DMA mode
2. PIO mode
3. Support for USB Audio and video class(UVC class)

USB OTG Driver

Description

MUSB controller on DaVinci supports USB On The Go (OTG). OTG protocol enables runtime role switch between USB host and device. This is achived using Session Request Protocol (SRP) and Host Negotiation Protocol (HNP). OTG driver is tested with OPT (OTG Protocol Tester).

Driver Features

The driver supports the following feature

eCAP

Description:

Enhanced Capture Module (eCAP) is used for speed measurements of rotating machinery, Sample Rate measurements of rotating machinery and Period and Duty Cycle measurements of pulse train signals. In PWM mode, eCAP can be configured to generate PWM Waveforms.

Driver Features:

1 .Supports Multiple Instances.
2. Provides control to the user through SYSFS interface.
3. Supports Wide range of Period and Duty cycle Control.

Constraint

eCAP driver belongs to the category of PWM drivers and hence the driver functions can be accessed only through the core PWM FrameWork.

eHRPWM

Description

Enhanced High-Resolution Pulse-Width Modulator (eHRPWM) is used to generate complex pulse width Waveforms with minimal CPU overhead or intervention.

Driver Features:

1 .Supports Multiple Instances.
2. Provides control to the user through SYSFS interface.
3. Supports wide range of Period and Duty cycle Control.
4. Supports Trip Zone, Dead Band, PWM chopper, Event Trigger and High Resolution Features.

Constraint

eHRPWM driver belongs to the category of PWM drivers and hence the basic PWM driver functions can be accessed only through the core PWM FrameWork. Advanced features have been exported for  global access.