MCU-PLUS-SDK-AM243X: SPI 3 pin Mode

Hi 

Duong Vu said:

so i change to 3 pin mode and uncheck the CS pin ( you can see in the picture), and when i build project, it has some error with makefile

I have raised a Jira ticket as an action to resolve this issue [MCUSDK-7371]. 

Regards

Sri Vidya

Hi

Please let us know if you need further support on this, for now closing this thread.

Regards

Sri Vidya

thank you very much. 
if you don't mind, i have a question, i wanna replace cs pin by gpio. is it okay ? 
Because i connect my MCU with some slaves, so i wanna use gpio (external cs )  to manually control the transfer process. So, i will use 3 pin mode SPI and uncheck the CS pin, right ? 
if you have any doccuments about this solutions, could you share these with me ? 
thanks a lot  !

Hi

Yes you can configure the SPI as 3 pin mode, If unchecking CS pin is causing compiler issue (will try to fix this issue by next release). As a workaround you select it (bypassing the sysconfig error) and then manually modify the Chip select code using GPIO Low and High APIs. (to support multiple slaves).

Currently there is no documentation available for this. You can follow the below link for reference:

e2e.ti.com/.../am2431-spi-single-master-using-multiple-chip-selects-for-4-nor-flash-parts-does-not-work

I think we can support multiple slaves connected to different CS lines as below -

• Configure the McSPI in 3 pin mode (CS not toggled by McSPI IP) only other 3 lines are used/toggled by McSPI
• Use GPIO to toggle the pin connected to CS of slave
• CS assertion is done by application using GPIO depending on which flash to be accessed and called across the McSPI transfer function.
• Initiate the McSPI transaction normally using same API for any of the flash devices.

Regards

Sri Vidya

Hi, 
Follow your instruction, i choose SPI 3 pin mode and still select CS_Pin. I choose GPIO pin as external CS pin.
I can Build project and no error with makefile. But the problem is i can't transfer the Data. i receive this notice when i debug the code ( you can see in the video) 
The process i do: 
- Configure the spi like this: 

- Set GPIO to low, transfer SPI data and set GPIO to high 
This is video i record when i debug my code. Could you see and give me some advice to fix this problem ? 
Thank you !

Hi

From the video you have shared, looks like your code is getting stuck into some exception after going into MCSPI_transfer.

Could you pause the code and check what is the exception you are getting?

Duong Vu said:

i receive this notice when i debug the code

By the notice, do you mean the "Could not read" error in the watch window? - This is because the code is running, you need to pause the code to read data through watch window.

Regards

Sri Vidya

Hi, 
Thanks for your reply, 
You 're right, the problem starts with the MCSPI_transfer function

I jump into MCSPI_transfer functions and continue step over to MCSPI_transferMasterPoll function. 

I step into the MCSPI_transferMasterPoll functions and continue step into to MCSPI_continueTxRx function. 
It repeats in the loop do while and the error is occurred 

Could you give me your advice to fix this problem ? 
Thank you very much .

Hi 

I was able to reproduce this issue at my end. I will discuss with the internal team on this and get back to you on the fix.

Regards

Sri Vidya

please show me when you find the way to fix this. 
thank you very much !