Issues Transmitting w/ SCI on the 68HC12

FallSe7en — Thu, 29 Oct 2020 09:07:38 GMT

Hi all,

I am trying to write to use the multiple serial interface on the 68HC12 but am can't get it to talk. I think I've isolated the problem to not being able to write to the SC1DRL register (SCI Data Register Low).

The following is an excerpt from my SCI ISR:

else if (HWRegPtr->SCI.sc1sr1.bit.tdre) {    /* Transmit the next byte in TX_Buffer. */    if (TX_Buffer.in != TX_Buffer.out || TX_Buffer.full) {        HWRegPtr->SCI.sc1drl.byte = TX_Buffer.buffer[TX_Buffer.out];        TX_Buffer.out++;        if (TX_Buffer.out >= SCI_Buffer_Size) {            TX_Buffer.out = 0;        }        TX_Buffer.full = 0;    }    /* Disable the transmit interrupt if the buffer is empty. */    if (TX_Buffer.in == TX_Buffer.out && !TX_Buffer.full) {        Disable_SCI_TX();    }}

TX_Buffer.buffer has the right thing at index TX_Buffer.out when its contents are being written to HWRegPtr->SCI.sc1drl.byte, but my debugger doesn't show a change, and no data is being transmitted over the serial interface.

Anybody know what I'm missing?

Re: Issues Transmitting w/ SCI on the 68HC12

FallSe7en — Wed, 10 Nov 2010 10:01:05 GMT

Some additional information...

HWRegPtr is a pointer to HARDWARE_REGISTER. HARDWARE_REGISTER is a giant volatile struct that has all the 68HC12 registers in it.

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Issues Transmitting w/ SCI on the 68HC12

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