AM35x McSPI FAQ

Content is no longer maintained and is being kept for reference only!

How can I get support?

• Technical Support
• Sitara E2E forums

What is TURBO mode

The turbo mode improves the throughput of the SPI interface when a single channel is enabled by allowing transfers until the shift register and the MCSPI_RXx register are full. The turbo mode is useful (time savings) when a transfer exceeds two words. This mode is programmable per channel (via the SPI1.MCSPI_CHxCONF[9] TURBO bit). When several channels are enabled, the TURBO bit has no effect.

TURBO mode can be used in TX/RX and RX only modes. TURBO mode can also be used with polling, FIFO, and DMA modes. TURBO mode can be combined with SINGLE mode.

Limitations

Only supports one enabled channel

TURBO mode does not by itself maintain CSn active between words (use SINGLE for this).

How do I keep CSn active between words?

To maintain an activce CSN between multiple words you need to set the SPI1.MCSPI_MODULECTRL[0] SINGLE bit. control of the CSn bit is now the responsibility of the software using the SPI1.MCSPI_CHxCONF[20] FORCE bit. The relationship between the FORCE bit and CSn signal is as follows:

– Writing 1 to the SPIm.MCSPI_CHxCONF[20] FORCE bit drives the SPIM_CSx line high when the SPIm.MCSPI_CHxCONF[6] EPOL bit is set to 0. SPIM_CSx is driven low when the SPIm.MCSPI_CHxCONF[6] EPOL bit is set to 1.

– Writing 0 to the SPIm.MCSPI_CHxCONF[20] FORCE bit drives the SPIM_CSx line low when the SPIm.MCSPI_CHxCONF[6] EPOL bit is set to 0. SPIM_CSx is driven high when the SPIm.MCSPI_CHxCONF[6] EPOL bit is set to 1.

Only a one channel can be enabled when using SINGLE mode.

From where can I download the BSL code for the AM3517 EVM?

• The latest BSL code can be downloaded from the Logic Website (registration required)

I want to connect my own SPI device to the AM3517 EVM or Experimenter Board. How can I do this?

Connector locations

McSpi1 signals are accessible via the following connectors

J25 on the application board of the AM3517 EVM:
pin 6 - MCSPI1_CLK
pin 5 - MCSPI1_SIMO
pin 8 - MCSPI1_SOMI
pin 7 - MCSPI1_CS0 

J29 on the application board of the AM3517 EVM:
pin 54 - MCSPI1_CLK
pin 56 - MCSPI1_SIMO
pin 58 - MCSPI1_SOMI
pin 52 - MCSPI1_CS0 

J22 (PERIPHERAL IO) on the Experimenter Board:
pin  82 - MCSPI1_CLK
pin  84 - MCSPI1_SOMI
pin  86 - MCSPI1_SIMO
pin  88 - MCSPI1_CS0
pin  90 - MCSPI1_CS1
pin  92 - MCSPI1_CS2
pin  94 - MCSPI1_CS3

McSPI2 signals are accessible via the following connectors

J22 (PERIPHERAL IO) on the Experimenter Board:
pin  95 - MCSPI2_CLK
pin  97 - MCSPI2_SOMI
pin  99 - MCSPI2_SIMO
pin 100 - MCSPI2_CS0
pin  98 - MCSPI2_CS1

McSPI3 signals are accessible via the following connectors
Note: MCSPI3 cannot be used with the full 24 bit video connector, 16 bit video is allowed. 

J29 on the application board of the AM3517 EVM:
pin 53 - MCSPI3_CLK  
pin 55 - MCSPI3_SIMO  
pin 57 - MCSPI3_SOMI 
pin 51 - MCSPI3_CS0  

J4 on the application board of the AM3517 EVM:
pin 26 - MCSPI3_CLK  
pin 25 - MCSPI3_SIMO  
pin 28 - MCSPI3_SOMI 
pin 27 - MCSPI3_CS0  

J23 (DEBUG IO) on the Experimenter Board:
pin  6 - MCSPI3_CLK
pin 10 - MCSPI3_SOMI
pin  8 - MCSPI3_SIMO
pin 12 - MCSPI3_CS0

McSPI4 signals are not accessible via any connector

Are AM3517 EVM/Experimenter Board schematics available?

• EVM and Experimenter Board schematics can be downloaded from the Logic Website (registration required)

What is the part number for the connector on the AM3517 experimenter board?

• To mate with J22 & J23 on the Experimenter Board - Hirose DF40C-100DP-0.4V(51) (100 PIN, .4MM PITCH, 1.5MM STACK HEIGHT )
• To populate J29 on EVM application board - Samtec SFM-150-02-S-D-LC (SOCKET, FEMALE, 0.050IN, 100 PIN, 2X50)
• To populate J25 on EVM application board - Molex 87831-1220 (HEADER, MALE, 0.100IN, 80PIN, 2X40)