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Altera_Forum's avatar
Altera_Forum
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16 years ago

Any ideas why this code isn't working

Backgroung, working with Terasic DE1 kit Trying to grab serial data from Copernicus Chip, interface http://www.sparkfun.com/datasheets/G...cus_Manual.pdf by default chip should give us $GPGGA onc...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

It seems like your treating the UART bitstream as synchronous 8 bit data stream, but it isn't. It has at least one stopbit and one startbit after 8 data bits, it uses basically a 10 bit frame.. Furthermore, it's not guaranteed, that the individual character frames are transmitted continuously. Instead, the UART receiver is expected to synchronize on each start bit a new. See http://en.wikipedia.org/wiki/uart for a brief explanation.