RTOS/DRA72XEVM: bsp uart edma function can not work

user5062300

Prodigy 130 points

Part Number: DRA72XEVM

Tool/software: TI-RTOS

when i use the ti driver components of M4, following error happened,

1、config the opmode UART_OPMODE_DMAINTERRUPT

2、config the event enable

3、send and receive messages in period task

4、debug my program，use the logic analyzer to read if the messages is right or not

what i found is that， the m4 was always sending 56 bytes “\0”,which is equal to txThreshold，and always receiving 8 bytes “\0”，which is equal to rxThreshold。

but actually，what i wanted to send is 0x01, 0x02....and receive is 0x01,0x02 in my program.

i checked the program , can't find the reason.

Is there someone have met the same thing as me? how can i solve this problem?

ps:when i config the opmode UART_OPMODE_INTERRUPT, it worked very well.

over 6 years ago

0 Yordan Kamenov over 6 years ago

TI__Mastermind 42515 points

Hi,

which SDK you use?

Regards,
Yordan

0 Sivaraj R3681 over 6 years ago in reply to Yordan Kamenov

TI__Expert 4935 points

Hi,

This is the current limitation of the UART driver - one can send only multiples of TX threshold and receive only multiples of RX threshold.

This is because of the complexity involved in maintaining different set of params when non-mutiple threshold transfer is required as well as interfacing EDMA with UART for transferring the last chunk of data.

There is no plan to implement this feature in the driver. Kindly use interrupt mode.

Regards

Sivaraj R

0 user5062300 over 6 years ago in reply to Yordan Kamenov

Prodigy 130 points

Hi
thanks for your reply, what i use is vision_sdk 2.9.

0 user5062300 over 6 years ago in reply to Sivaraj R3681

Prodigy 130 points

Hi
Thanks for your reply, i still have 2 questions。
1、Is it means that if i want to use the edma to send non-mutiple datas，i should change the driver to solve it？
2、why did the value of all sended and recieved datas are '\0', not what i wrote in program which are 0x01, 0x02,0x3.....,in the same time, the line error interrupt always happened?

0 Sivaraj R3681 over 6 years ago in reply to user5062300

TI__Expert 4935 points

Yes. But one way to make this work is by setting the threshold to 1 bytes. This will generate one DMA event per byte and hence is not efficient and will hog the EDMA/L3.

I did not understand the second question.

0 user5062300 over 6 years ago in reply to Sivaraj R3681

Prodigy 130 points

sorry for replying so late，

the second question as following：

1、i send the array test[9] = {0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09} by uart edma.

2、then use the logic analyzer to monitor if the output datas from uart's txd port are whether i send .

3、well，outout datas rrom uart port are {0x00,0x00,0x00,0x00....0x00},which size are 56 byte. not {0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09} .

so i do not know why did it happen.

0 Sivaraj R3681 over 6 years ago in reply to user5062300

TI__Expert 4935 points

This could be because of cache. Before providing the buffer to the driver ensure that the buffer is flushed and the content is written to the actual memory.

The 56 bytes (instead of 9 bytes)could be because of the threshold limitation I have mentioned earlier.

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RTOS/DRA72XEVM: bsp uart edma function can not work