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Altera_Forum
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13 years ago

UART Transmitter Sends Bytes Out of Order

Hello, I have the following Verilog code which sends 8 bytes to the serial port successively after a button is pressed. The problem is, the bytes are sent out of order as to what I would e...
Altera_Forum's avatar
Altera_Forum
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13 years ago

There isn't quite enough here to go on, but I'll hazard a guess. The code for uart1 is critical.

If the isTransmitting signal is generated using a clocked process, (sorry for the terminology, I'm a VHDL guy) the isTransmitting signal will go high at least 1 clock after begin_transmit is set high. This will cause if(!isTransmitting) to be true.

A Verilog simulator would probably show you exactly what is going on. If you are still stuck on this, post the uart code. It will help fill in the gaps.