I Think I solve the Autobaud rate rutine

[Acetoel]

Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
Here I the rutine

Unsigned Int16 Count1,Count2,Count3,Speed

While(RXPin){}
While(!RXpin) {
delay_us(1); //Think that some NOPs will be better
count1++;
}
While(RXpin){
delay_us(1);
count2++;
}
While(!RXpin){
delay_us(1);
count3++;
}
Speed = (Count1 + count2 + Count3) / 3

//Well, and then I load the "Speed"into the Serial Register

Ezequiel
___________________________
This message was ported from CCS's old forum
Original Post ID: 12717

[Sherpa Doug]

:=Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
:=So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
:=Here I the rutine
:=
:=Unsigned Int16 Count1,Count2,Count3,Speed
:=
:=While(RXPin){}
:=While(!RXpin) {
:= delay_us(1); //Think that some NOPs will be better
:= count1++;
:=}
:=While(RXpin){
:= delay_us(1);
:= count2++;
:=}
:=While(!RXpin){
:= delay_us(1);
:= count3++;
:=}
:=Speed = (Count1 + count2 + Count3) / 3
:=
:=//Well, and then I load the "Speed"into the Serial Register
:=
:=Ezequiel

The basic idea is good, but I might check that all three counts are about the same. If one is way off discard it.

___________________________
This message was ported from CCS's old forum
Original Post ID: 12766

[Neutone]

:=Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
:=So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
:=Here I the rutine
:=
:=Unsigned Int16 Count1,Count2,Count3,Speed
:=
:=While(RXPin){}
:=While(!RXpin) {
:= delay_us(1); //Think that some NOPs will be better
:= count1++;
:=}
:=While(RXpin){
:= delay_us(1);
:= count2++;
:=}
:=While(!RXpin){
:= delay_us(1);
:= count3++;
:=}
:=Speed = (Count1 + count2 + Count3) / 3
:=
:=//Well, and then I load the "Speed"into the Serial Register
:=
:=Ezequiel

Concider this. Jump baud when count of framing errors reaches 32.

#int_RDA2
RDA_isr()
{int8 x;
if(bit_test(RS232_ERRORS,2))
{RS232_ERRORS=0;
++ChanBErrors;
if(bit_test(ChanBErrors,5))
BaudChanB();}
else
{x= fgetC(ChanB);
ChanBinBuff[ChanBinIndex++] = x;
set_timer1(ChanBtimeout);
bit_clear(*0xF9E,0);
enable_interrupts(int_TIMER3);}}


The function BaudChanB(); jumps to the next slower baud rate. Baud jumping stops when the correct rate is achieved.
___________________________
This message was ported from CCS's old forum
Original Post ID: 12767

[Acetoel]

Hi,
Neutone, I didn't understand your rutine. And just to remember I received 0x55 only one time.
Sherpa, How I can load that value directly into the hardware port register?
Thanks to everybody
Ezequiel

:=:=Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
:=:=So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
:=:=Here I the rutine
:=:=
:=:=Unsigned Int16 Count1,Count2,Count3,Speed
:=:=
:=:=While(RXPin){}
:=:=While(!RXpin) {
:=:= delay_us(1); //Think that some NOPs will be better
:=:= count1++;
:=:=}
:=:=While(RXpin){
:=:= delay_us(1);
:=:= count2++;
:=:=}
:=:=While(!RXpin){
:=:= delay_us(1);
:=:= count3++;
:=:=}
:=:=Speed = (Count1 + count2 + Count3) / 3
:=:=
:=:=//Well, and then I load the "Speed"into the Serial Register
:=:=
:=:=Ezequiel
:=
:=The basic idea is good, but I might check that all three counts are about the same. If one is way off discard it.
:=
___________________________
This message was ported from CCS's old forum
Original Post ID: 12785

[Sherpa Doug]

:=Hi,
:= Neutone, I didn't understand your rutine. And just to remember I received 0x55 only one time.
:= Sherpa, How I can load that value directly into the hardware port register?
:=Thanks to everybody
:=Ezequiel
:=

I have never done that. I just use the #useRS232 statements. I suggest you read the Microchip datasheet on your PIC. The UART registers should be well explained. Use #define to label the register's location and then write to it just like it was a port.

___________________________
This message was ported from CCS's old forum
Original Post ID: 12787

[Neutone]

:=Hi,
:= Neutone, I didn't understand your rutine. And just to remember I received 0x55 only one time.
:= Sherpa, How I can load that value directly into the hardware port register?
:=Thanks to everybody
:=Ezequiel
:=
:=:=:=Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
:=:=:=So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
:=:=:=Here I the rutine
:=:=:=
:=:=:=Unsigned Int16 Count1,Count2,Count3,Speed
:=:=:=
:=:=:=While(RXPin){}
:=:=:=While(!RXpin) {
:=:=:= delay_us(1); //Think that some NOPs will be better
:=:=:= count1++;
:=:=:=}
:=:=:=While(RXpin){
:=:=:= delay_us(1);
:=:=:= count2++;
:=:=:=}
:=:=:=While(!RXpin){
:=:=:= delay_us(1);
:=:=:= count3++;
:=:=:=}
:=:=:=Speed = (Count1 + count2 + Count3) / 3
:=:=:=
:=:=:=//Well, and then I load the "Speed"into the Serial Register
:=:=:=
:=:=:=Ezequiel
:=:=
:=:=The basic idea is good, but I might check that all three counts are about the same. If one is way off discard it.
:=:=

What is the device you are communicating with? The routine I posted is based on recieving periodic packet transmition or bytes. Baud is adjusted untill incomming packets are free of framing errors.
___________________________
This message was ported from CCS's old forum
Original Post ID: 12789

[Acetoel]

I'm communication with a VW GOL Electronic Control Unit. This unit send 0x55 only one time, and the continue sending information, there is 30ms between I rcv 0x55 and the first byte of info. that is way I need to use 0x55 to detect the baudrate at ones.
Thanks
Ezequiel

:=:=Hi,
:=:= Neutone, I didn't understand your rutine. And just to remember I received 0x55 only one time.
:=:= Sherpa, How I can load that value directly into the hardware port register?
:=:=Thanks to everybody
:=:=Ezequiel
:=:=
:=:=:=:=Well, justo to remember I'm using a 16F76 at 20MHz, using the Hardware UART and I receive 0x55 from a terminal, which speed of comm. I don't know.
:=:=:=:=So I use the pin as a normal input, and wait the start bit, measure it, and two more bits. then take and average and load the baudrate directly to the Serial Port Register.
:=:=:=:=Here I the rutine
:=:=:=:=
:=:=:=:=Unsigned Int16 Count1,Count2,Count3,Speed
:=:=:=:=
:=:=:=:=While(RXPin){}
:=:=:=:=While(!RXpin) {
:=:=:=:= delay_us(1); //Think that some NOPs will be better
:=:=:=:= count1++;
:=:=:=:=}
:=:=:=:=While(RXpin){
:=:=:=:= delay_us(1);
:=:=:=:= count2++;
:=:=:=:=}
:=:=:=:=While(!RXpin){
:=:=:=:= delay_us(1);
:=:=:=:= count3++;
:=:=:=:=}
:=:=:=:=Speed = (Count1 + count2 + Count3) / 3
:=:=:=:=
:=:=:=:=//Well, and then I load the "Speed"into the Serial Register
:=:=:=:=
:=:=:=:=Ezequiel
:=:=:=
:=:=:=The basic idea is good, but I might check that all three counts are about the same. If one is way off discard it.
:=:=:=
:=
:=What is the device you are communicating with? The routine I posted is based on recieving periodic packet transmition or bytes. Baud is adjusted untill incomming packets are free of framing errors.
___________________________
This message was ported from CCS's old forum
Original Post ID: 12792