OMAP35x Power Estimation Tool

Introduction

The Power Estimation Tool (PET) provides users the ability to gain insight in to the power consumption of select Sitara processors. The tool includes the ability for the user to choose multiple application scenarios and understand the power consumption as well as how advanced power saving techniques can be applied to further reduce overall power consumption.

PET is comprised of three modules:

1. Input Spreadsheet – this downloadable spreadsheet is the mechanism in which users input device parameters needed for their application. Parameters include IP activities/loadings, desired power states, and power management usages. Multiple operating conditions can be applied along with time slots for each state.
2. Spreadsheet Upload- upon completion of the input spreadsheet, users can then upload the spreadsheet to TI for the power consumption analysis. Registration and legal agreement acceptance is required for the upload.
3. Power Analysis Report-contains the information on power consumption based on the spreadsheet upload. The report includes leakage, active and total average power, as well as power management voltages will be sent to the user via email.

Input Spreadsheet

There are two types of input spreadsheet. Standard input spreadsheet is designed for estimating the power for single application scenario. Advanced input spreadsheet has additional columns for multiple application scenarios. The power estimates from advanced input spreadsheet will be an average power of multiple application scenarios that configured in the input spreadsheet.

The input spreadsheet consists of 4 sections: tables A, B, C and D. Using the input spreadsheet involves simply entering appropriate usage parameters. Cells that are designed for user input are light green in color. To use the spreadsheet, simply configure the light green cells to a value most closely aligned with your intended scenario.

Briefly, the purpose of each of the 4 sections is:

• Section A: configure the high-level system configuration such as junction temperature and power estimation mode.
• Section B: configure ARM and IVA subsystem components.
• Section C: configure peripherals and graphics accelerator.
• Section D: configure analog macros.

The spreadsheet applies to OMAP3530, OMAP3525, OMAP3515 and OMAP3503 devices.

Download OMAP35x PET Input Spreadsheet here.

The spreadsheet includes macros. If you can't run macros, please review your excel security settings described in below articles.
Change macro security settings in Excel (Office 2007)
Enable macros to run (Office 2003)

Macro Buttons

The input spreadsheet has command buttons to run macros as shown in Figure 1.

Figure 1. Macro Buttons

1. "Click to Submit" - Navigate to upload page.
2. "Default Settings" - Clear all settings and make them to default values.
3. "Music Playback Example" - Configure settings to music playback example application scenario.
4. "Video Capture Example" - Configure settings to video capture example application scenario.
5. "Off Mode Example" - Configure settings to Off Mode example application scenario.

Section A: High-Level System Configuration

This section allows the user to set a junction temperature (not ambient temperature) between 0C and 105C, power estimation mode and power management features as shown in Figure 2.

Figure 2. Section A of OMAP35x PET input spreadsheet allows configuration of junction temperature, power estimation mode SmartReflex and DPS.

• Junction Temperature (°C) : 0 ~ 105 (Negative value is not supported in the tool)
• Power Estimation Mode : Max, Typ
• Smart Reflex : On, Off
• Mode : Active, Standby1, Standby2, Standby3, Standby4 or Off mode
• Dynamic Power Switching : On, Retention or Off

Table 1. The states of power domains in OMAP35x in standby modes.

Modules	Standby1	Standby2	Standby3	Standby4	OFF
MPU	Retention	Retention	Off	Off	Off/0V
IVA	Retention	Off	Off	Off	Off/0V
SGX	Retention	Off	Off	Off	Off/0V
CORE	Retention	Retention	Retention	Off	Off/0V
DISP	Retention	Retention	Off	Off	Off/0V
CAM	Retention	Off	Off	Off	Off/0V
PER	Retention	Off	Off	Off	Off/0V
EMU	Off	Off	Off	Off	Off
WUKP	Active	Active	Active	Active	Active

Off-mode (or Device Off-mode) is the lowest power state from which the OMAP35x can still wakeup autonomously. In this device state all domains are powered off except for the wakeup domain (VDD3). The unused external supplies can also be shut off to conserve power. Off-mode is distinct from Full Off, where no part of the OMAP35x is powered on.

The spreadsheet presents information for only the full-featured OMAP3530 device in OMAP35x family. However, since the spreadsheet breaks out the power consumption due to each module in the OMAP3530, estimates for the OMAP3525, OMAP3515 and OMAP3503 can be obtained by setting zero for the module not present in the device under consideration. This will ensure active power from the non-applicable module is not included in the power tally. The device differences are summarized as follows:

• OMAP3530 (device with ARM, IVA and SGX)
• OMAP3525 (device with ARM and IVA)
• OMAP3515 (device with ARM and SGX)
• OMAP3503 (ARM only device)

Section B: Processors

This section allows the user to set an operating performance point (OPP) for the ARM and IVA subsystems, as shown in Figure 3.

Figure 3. Section B of the OMAP35x input spreadsheet allows configuration of processors' OPP and utilization).

The OPP options supported for the ARM and IVA subsystems voltage domain (VDD_MPU_IVA) are shown in Table 2 below.

Table 2. Operating performance point definitions for the processor subsystems.

Processors' OPP	VDD_MPU_IVA (V)	ARM MHz	IVA MHz
1	0.985	125	90
2	1.06	250	180
3	1.20	500	360
4	1.27	550	400
5	1.35	600	430
6	1.35	720	520

The OPP options supported for the modules powered by the VDD_CORE rail are shown in Table 3 below.

Table 3. OPP3 definitions for VDD_CORE components.

Core OPP	VDD_CORE (V)	L3_ICLK MHz	L4_ICLK MHz	SDRC_CLK MHz	GPMC_CLK MHz
1	0.985	41.5	20.75	41.5	41.5
2	1.06	83	41.5	83	83
3	1.15	166	83	166	83

Module utilization is the percentage of the available MHz at the selected OPP needed to meet the scenario processing requirement.

A separate utilization entry is provided for the Cortex-A8 ARM processor and the NEON SIMD engine.

1. Cortex-A8 (ARM Cortex-A8 processor core)
2. Cortex-A8 NEON (General purpose SIMD engine)

For the IVA subsystem, a separate utilization entry is provided for each of the following IVA subsystem components:

1. IVA DSP (C64x+ Digital Signal Processor)
2. SEQ (Sequencer)
3. iLF (improved Loop Filter)
4. iME (improved Motion Estimator)
5. iVLCD (improved Variable-Length Coder/Decoder)

For the graphics accelerator subsystem, a separate utilization entry is provided:

1. SGX (2D/3D graphics accelerator engine)

Section C: Core Modules

This section is used to configure the activity on peripheral modules as shown in Figure 4.

Figure 4. Section C of the OMAP35x PET Input Spreadsheet allows configuration of peripherals.

The utilization of video/imaging interface modules such as DSS (Display Sub-System) and CAM/ISP (camera/image signal processing sub-system) are configured by the following parameters.

• Horizontal Pixels : 0 ~ 1368
• Vertical Pixels : 0 ~ 768
• Frame per Second : 0 ~ 60
• Bit per Pixel : 0 ~ 32
• Blanking Period [%] : 0 ~ 10

For each modules, a user can enter module utilization as a percentage. A separate utilization entry is provided for the following modules.

• SDMA (system direct memory access controller)
• SDRC (SDRAM controller)
• GPMC (general purpose memory controller)
• USB (universal serial bus)
• MMC (multimedia card host controller)
• McBSP (multi-channel buffered serial port)
• UART (universal asynchronous receiver/transmitter)
• GPTIMERS (general purpose timers)
• MISC. PERIPHERALS (other miscellaneous peripherals such as I2C, SPI and GPIO modules)

Section D: Analog Modules

Section D enables a configuration for analog modules in the OMAP35x as shown in Figure 5 below.

Figure 5. Section D of the OMAP35x PET Input Spreadsheet allows for the configuration of analog modules.

• VDAC (Video DAC) : On or Off

Spreadsheet Upload

Upon completion of the input spreadsheet, users can then upload the spreadsheet to TI for the power consumption analysis. Registration and legal agreement acceptance is required for the upload.

Upload your OMAP35x PET Input Spreadsheet here.

Power Analysis Report

Power Estimation Report Sheet

The power estimation tool generates a power analysis report is a spreadsheet format (See Figure 6). The estimated values are leakage, active and total average power over the time during the entire application scenario. It is also listed per power rail groups. When SmartReflex (AVS) is enabled, processor and core voltage rails show controlled voltages by Smart Reflex.

Figure 6. Power Estimation Report.

Power consumption in the OMAP35x device consists of:

• leakage power – due to leakage current, and dependent on temperature and device process; and
• active power – due to transistor switching, and independent of temperature.

The OMAP35x Power Estimation Tool models temperature and device process effects on device power consumption. Active power consumption is the power that is consumed by portions of the OMAP35x that are performing some processing. Active power is independent of temperature, but dependent on voltage and module activity levels.

Module Utilization Sheet

The available bandwidth for each module depends on the device interconnects architecture and a selected CORE OPP. The power estimation tool calculates current module bandwidth from utilization entered by user and shows the results for each time slot with the maximum available bandwidth for the selected OPP in separate sheet (See Figure 7).

Figure 7. Maximum Module Utilization.

Important Notes and Limitations

The following notes and limitations apply to the OMAP35x Power Estimation Tool:

• It is up to the user to input reasonable utilization numbers for the MPU and IVA subsystems for the purposes of maximum power analysis. 90-100% loading on either subsystem is not realistic for most application scenarios.

References

1. OMAP3530 Power Estimation Spreadsheet ([1]).

Revision History

Date	Modification
1/6/11	Version 1.00. Initial version.