Post by thread:9600 8 N 1 on PIC16c74A

I am trying to get a PIC16c74A to receive a 9600 baud 8 data bit, no parity, 1 stop bit signal. I have configured the serial port with the following options: Crystal:5.0688 MHz RCSTA:0x90 TXSTA:0xA4 SBRGH:32 Is this all I need? The strange thing is that it actually communicates fairly well. However, approximately 2-4 bytes out of every 100 received are completely wrong. There doesn't seem to be a pattern. Some are off by 0xCC or 0x7D or 0x8F or 0xBF, etc. Any ideas? Jason

Jason R Williamson wrote: > > I am trying to get a PIC16c74A to receive a 9600 baud 8 data bit, > no parity, 1 stop bit signal. I have configured the serial port > with the following options: > would you mind sending the initialization codefragment (or the whole routine) to me , I'm working on the same problem with a 16c65 the usart is the same , but I can't make it work . it must be something simple , trivial - but I can't see problem :( bye charley

>I am trying to get a PIC16c74A to receive a 9600 baud 8 data bit, >no parity, 1 stop bit signal. I have configured the serial port >with the following options: > >Crystal:5.0688 MHz > >RCSTA:0x90 >TXSTA:0xA4 >SBRGH:32 > >Is this all I need? The strange thing is that it actually communicates >fairly well. However, approximately 2-4 bytes out of every 100 received >are completely wrong. There doesn't seem to be a pattern. Some are off >by 0xCC or 0x7D or 0x8F or 0xBF, etc. > >Any ideas? > Hi Jason, Choose a XTAL that gives 9600 baud with BRGH=0, this increases the sampling to x64 mode and should fix the above problem. Ray Gardiner (DSP Systems) spam_OUTrayTakeThisOuTdsp-systems.com http://www.dsp-systems.com private email to:- .....rayKILLspam@spam@netspace.net.au

Sure. Enjoy. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;SETUP_COMM ; Setup the asynchronous comm. stuff ; inputs: baudrate, TXSTA_INIT, RCSTA_INIT ; outputs: none ; calls: none setup_comm bsf STATUS,RP0 ; switch to bank 1 movlw baudrate movwf SPBRG ;set baudrate ;these are the only two cnnctns for serial comm. bsf TRISC, 7 ;bit7 input (RX) bcf TRISC, 6 ;bit6 output (TX) movlw TXSTA_INIT movwf TXSTA bcf STATUS, RP0 ; switch to bank 0 movlw RCSTA_INIT movwf RCSTA return That's it. Let me know if you have any questions. Jason {Quote hidden}> Jason R Williamson wrote: > > > > I am trying to get a PIC16c74A to receive a 9600 baud 8 data bit, > > no parity, 1 stop bit signal. I have configured the serial port > > with the following options: > > > > would you mind sending the > initialization codefragment (or the > whole > routine) to me , I'm working on the same > problem with a 16c65 > the usart is the same , but I can't make > it work . > it must be something simple , trivial - > but I can't see problem :( > > bye > charley >

P.S. This is pretty well-known, but just in case, don't forget to use something to invert the input/output!!! ---------- {Quote hidden}> From: Jason R Williamson <jrwill01KILLspamSTARBASE.SPD.LOUISVILLE.EDU>> > To: .....PICLISTKILLspam.....MITVMA.MIT.EDU > Subject: Re: 9600 8 N 1 on PIC16c74A > Date: Monday, February 16, 1998 2:40 PM > > Sure. Enjoy. > > ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; > ;SETUP_COMM > ; Setup the asynchronous comm. stuff > ; inputs: baudrate, TXSTA_INIT, RCSTA_INIT > ; outputs: none > ; calls: none > setup_comm > bsf STATUS,RP0 ; switch to bank 1 > > movlw baudrate > movwf SPBRG ;set baudrate > > ;these are the only two cnnctns for serial comm. > bsf TRISC, 7 ;bit7 input (RX) > bcf TRISC, 6 ;bit6 output (TX) > > movlw TXSTA_INIT > movwf TXSTA > > bcf STATUS, RP0 ; switch to bank 0 > movlw RCSTA_INIT > movwf RCSTA > > return > > That's it. Let me know if you have any questions. > > Jason > > > Jason R Williamson wrote: > > > > > > I am trying to get a PIC16c74A to receive a 9600 baud 8 data bit, > > > no parity, 1 stop bit signal. I have configured the serial port > > > with the following options: > > > > > > > would you mind sending the > > initialization codefragment (or the > > whole > > routine) to me , I'm working on the same > > problem with a 16c65 > > the usart is the same , but I can't make > > it work . > > it must be something simple , trivial - > > but I can't see problem :( > > > > bye > > charley > >