SPI EasyDMA MAXCNT limitation

RE: SPI EasyDMA MAXCNT limitation

Coldson — Thu, 12 May 2016 16:36:18 GMT

Hi @Aryan __on Vacation till week 30, can u kindly provide me more informant for SPI list feature. I try to send large data through SPI, but I found out that length type is uint8_t only can transfer 255 byte at a time, will SPI LIST feature fix my problem? Thx

RE: SPI EasyDMA MAXCNT limitation

Susheel Nuguru — Thu, 28 Jan 2016 09:47:08 GMT

split up your array into 12 bytes buffer and use the LIST feature to transmit/receive 31 samples in succession.

This array list does not provide a mechanism to explicitly specify where the next item in the list is located.  Instead, it assumes that the list is organized as a linear array where items are located one after the other in RAM.

The above feature will help you transmit what you want. Remember that this does not happen automatic, If you want it to automatically transfer array list one after the another, you need to use PPI to trigger the next transaction when the previous one ended.

RE: SPI EasyDMA MAXCNT limitation

Cyril — Thu, 28 Jan 2016 09:37:01 GMT

Looking at the doc, it's a 32-bit register but only 8 bits are used, it makes sense! Thank you!! I'll look into the List feature then!

RE: SPI EasyDMA MAXCNT limitation

Susheel Nuguru — Thu, 28 Jan 2016 09:32:28 GMT

isn't MAXCOUNT 8 bit register? so max is 255 bytes. If you want to transfer more, you can use the LIST feature