Hi All,
I am using the MC908QB8 Demo Board and CW50. I have read through the manual and looked through the posts on this forum for help. I am trying to simply poll the SCI register for an incoming char and then transmit it out the SCI port. My code is listed below, as far as I understand the steps are:
1. Check for the SCI Recevier Full Flag. (SCRF)
2. Read the SCI Data Register
3. Check for the SCI Transmitter Empty flag. (SCTE)
4. Write the SCI Data Register
// SCI Loop Test
for(;
/* loop forever */
{
__RESET_WATCHDOG(); /* feeds the dog */
for(;
/* loop forever */{
__RESET_WATCHDOG(); /* feeds the dog */
if(SCS1_SCRF) // SCRF Bit - Check for char ready and clear bit
{
RChar = SCDR; // Get SCI Char
while(!SCS1_SCTE) //SCTE Bit - wait for transmitter empty
;
SCDR = RChar; // Send SCI char
}
}
;
SCDR = RChar; // Send SCI char
}
}
My code is not working, any help please?
Thanks,
David Evennou
OK, got it! I just commented the code from the last test and added the new code below it. At first it did not work even though it should have. Then I remembered that somewhere along the way yesterday I picked up some code from another project and enabled the SCI transmitter by using SCC2 = 0x08. Oh no, this code turns off the receiver! I changed the transmitter enable code to, SCC2_TE = 1, and now the QB8 is echoing chars.
I have made a number of code additions and changes over the past few days, so I need to go back to the original code and compare with the changes I made. My goal is to receive a string of 8 characters into a buffer and then do some work with that data. Now at least I know the serial receive part is working!
Thanks so much for all of your help!!
David
LED1 = OFF;
LED2 = OFF;
LED2 = OFF;
SCC2_RE = 1; // enable Rx
// SCC2 = 0x08; // enable Tx
SCC2_TE = 1; // enable Tx
// SCC2 = 0x08; // enable Tx
SCC2_TE = 1; // enable Tx
// SCI Loop Test
for(; /* loop forever */
{
__RESET_WATCHDOG(); /* feeds the dog */
for(;
/* loop forever */{
__RESET_WATCHDOG(); /* feeds the dog */
// if(SCS1_SCRF) // SCRF Bit - Check for char ready and clear bit
// LED1 = ON;
// if(SCS1_OR) // Overrun Bit - Check for missed char read
// LED2 = ON;
if(SCS1_SCRF) // SCRF Bit - Check for char ready and clear bit
{
LED1 = ON;
RChar = SCDR; // Get SCI Char
// LED1 = ON;
// if(SCS1_OR) // Overrun Bit - Check for missed char read
// LED2 = ON;
if(SCS1_SCRF) // SCRF Bit - Check for char ready and clear bit
{
LED1 = ON;
RChar = SCDR; // Get SCI Char
while(!SCS1_SCTE); //SCTE Bit - wait for transmitter empty
LED2 = ON;
SCDR = RChar; // Send SCI char
}
}
LED2 = ON;
SCDR = RChar; // Send SCI char
}
}
OK, Good News! I plugged in the code below and that works OK, got characters in HyperTerminal.
So now, how can I get the SCI Rx working?
Thanks,
David
David
void MCU_init(void); /* Device initialization function declaration */
void Delay(byte time);
void main(void) {
MCU_init(); /* call Device Initialization */
for(; {
while(!SCS1_TC); SCDR = 0x55;
Delay(5);
} /* loop forever */
}
void Delay(byte time)
{
word i;
for(i = 0;i < time*255; i++)
{
__RESET_WATCHDOG();
}
}
Hi Peg,
This code works OK. When I send one character, LED1 comes ON. Then LED2 comes ON when I send the next character over RS-232. It makes sense, the Overrun bit is set becuse the data register has not been read when the 2nd char is received.
Thanks,
David
David
LED1 = OFF;
LED2 = OFF;
LED2 = OFF;
SCC2_RE = 1; // enable Rx
// SCI Loop Test
for(; /* loop forever */
{
__RESET_WATCHDOG(); /* feeds the dog */
for(;
/* loop forever */{
__RESET_WATCHDOG(); /* feeds the dog */
if(SCS1_SCRF) // SCRF Bit - Check for char ready and clear bit
LED1 = ON;
if(SCS1_OR) // Overrun Bit - Check for missed char read
LED2 = ON;
}
LED1 = ON;
if(SCS1_OR) // Overrun Bit - Check for missed char read
LED2 = ON;
}
