TMS570 - EMIF & SCI

pavithra pavithra

Intellectual 870 points

Other Parts Discussed in Thread: TMS570LC4357

hi ti,

i m using TMS570LC4357

i have written a code to blink led and send ACK upon reception of corresponding commands.

led blink function is copied to sdram using emif and is called in sci isr.

if i simply receive a frame i can transmit ACK(sci txn works properly). but if i receive frame respective to

led blink function, the function is called correctly but after that i cant send ACK (sci txn is not working).

sci transmits the ACK only ater receiving another fame.(ie. txn happens when rx int is detected).

why this s happening? i need to send the ACK immediately after calling the func.

sci settings:

baud rate=115200; data bits=8; stop bits=1; enabled rx int and tx int; mode= address bit mode;

should i ve to enable some other settings??

over 10 years ago

0 pavithra pavithra over 10 years ago

Intellectual 870 points

after function call, if i transmit the first byte of ACK frame TXRDY=1; TXEMPTY=1; but INTVECT0 = 11U;

is transmission interrupt not generated???

0 Enrique Lizarraga over 10 years ago in reply to pavithra pavithra

TI__Expert 4580 points

Hello:

I'll direct your post to one of our experts to assist you.

Regards.

0 pavithra pavithra over 10 years ago in reply to Enrique Lizarraga

Intellectual 870 points

hello team,

pls respond to my issue...

this is the command and ack for led blink function.

but what i receive is

and i receive this only after sending the command once again.

why transmission of ack happens after receiving another frame?

why the transmit buffer is filled with zeros?

why the first byte is missing?

pls help me to solve this issue.

thanks

0 pavithra pavithra over 10 years ago in reply to pavithra pavithra

Intellectual 870 points

this is the correct ack

but what i receive is this

0 Charles Tsai over 10 years ago in reply to pavithra pavithra

TI__Guru**** 191826 points

Hello Pavithra,

I can't quite follow the diagrams you attached. You have the Write Request Down and the Read Request Up. Is the Write Request coming from outside and the Read Request Up is the data the LC4357 trying to ACK?

I'm not sure why you would want to copy and execute the LED blink function in SDRAM? the EMIF interface is only 16bit. If you have a cache miss, the CPU will need to perform a cache refill to retrieve the LED blink function from the SDRAM and this will take quite some time.

In order to isolate the problem can you try to execute the LED blink function from the internal flash? Can you please tell me if this makes a difference to the behavior?

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TMS570 - EMIF & SCI