Justin Lei

Issues Transmitting w/ SCI on the 68HC12

Discussion created by Justin Lei on Nov 10, 2010
Latest reply on Nov 10, 2010 by Justin Lei

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?