Hello,
I want to test the uPP on the DSP C6748. I wrote a little program that send a buffer of 100 bytes. The buffer is constituted of a counter that is counting from 0 to 99.
To receive the data, I configure the uPP in loopback mode.
When the interrupt EOW is activated, i 'm going to read the data and check them.
I put my test in a loop. Most of the time, the test is OK that is the received data are good (data are incremented from 0 to 99) but sometimes my test failed. In that case, I noticed that 8 bytes were always introduced in my data.
For example :"…… 37363534 3B3A3938 07060504 0B0A0908 3F3E3D3C 43424140 47464544 ……" is received but KO because of the added "07060504 0B0A0908" sequence. The other data (before and after) are good.
I notice that the 8 bytes that are introduced are always the same "07060504 0B0A0908".
In my test I manage only 2 interrupts : timer interrupt (for my OS) and uPP interrupt.
I noticed that if I disable the timer interrupt , my test is always OK and never failed.
Thus finally I suppose that the interrupt interact with the functioning of the uPP but I don’t know How ?
I wanted to add that I tried to disable and enable global interrupt when I program read/write on uPP register (UPQD0/UPQD1/UPQD2, UPID0/UPQI1/UPQI2) but it didn’t change anything.
Any help would be appreciated, thank you very much in advance, Patrick