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Altera_Forum's avatar
Altera_Forum
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11 years ago

JTAG UART repeating characters on Cyclone IV Transciever Kit

I am not sure what is up ... I have tried JTAG_UART with interrupt and polling ( with small model ) and there doesn't seem much difference. If I fun printf("Hello\n"); ten times through a loop, ...
Altera_Forum's avatar
Altera_Forum
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11 years ago

I'm thinking this JTAG UART is similar to semi-hosting .. the stdio is directed to hardware buffers and the buffer is unloaded via the JTAG connection to Eclipse. If the characters get to the buffer correctly then repeating characters could be on the JTAG / Eclipse driver side.

To debug I have tried reducing the buffer depth and threshold and changing from interrupt mode to polled mode.

I guess I can try to debug in Eclipse and see if the correct number of characters are delivered by the putc routing called from printf.

Th other thing I could do is to switch to a real UART and would like to use a "USB JTAG" conenction but don't think the Cyclone kit has such a facility ?

All the time I worked with Arria , the JTAG UART worked fine.