TMDS64EVM: Start DMA using timer interrupt signal

Kiyomasa Imaizumi said:

I'd like to run DMA using a timer interrupt on the AM64 CR5 core.
Is it possible to run DMA using the timer interrupt signal as a trigger without writing code to start DMA in the timer interrupt handler function?
Please let me know if you have any sample code.

Kiyomasa Imaizumi said:

Is it possible to synchronize two other timers (for example TIMER1 and TIMER2) and start counting?
If there is a way to do this, please let me know the code.

Hello Kiyomasa Imaizumi.,

Hello Swargam Anil

Regarding the question I asked in private chat, when can you expect a reply?

Best regards,

Kiyomasa Imaizumi.

Hello Swargam Anil.

How is the progress since then?
Please contact us.

Best regards,
Kiyomasa Imaizumi.

Hello Kiyomasa Imaizumi,

Sorry for the delayed replies. Your requirements are as below.

For the 128KHz we need to transfer 1Byte on the SPI TX line.

After completion of the above 32 transactions, which exactly complete the 0.25msec(4KHZ), we need to transfer same one byte of data on the SPI line with a different buffer.

Based on my analysis, the DMA is not used for lower data rates, like 1byte, and it is not possible to achieve your requirements with the DMA.

I hope your application can be implemented with SPI +Timer only and go with the SPI LLD driver.

In this case, the SPI is directly written to the Register level.

But, here you frequently get interruptions by 7.8usec.

Implementation Approach:
1. Configure a Timer:
• Set it up to trigger an interrupt every 7.8 µs (128 kHz).
• In the ISR, write 1 byte to the SPI TX register.
2. Use SPI in Register Mode (LLD):
• Directly write the data to the SPI data register.
• Ensure the SPI peripheral completes the transmission before sending the next byte.
3. Handling 4 kHz Buffer Switching:
• After 32 SPI transfers (0.25 ms), switch to a different buffer.
• This logic can be handled in the timer ISR .