Interrupt driven Buffered Serial Input

Hi, I'm going mad for the past few days here since my interrupts are not working. I am trying to make a interrupt driven buffered serial input but without success since my program doesn't do anything when it should deal with the interrupts (it just stays on that "While CounterA <= 70 : WEND" forever) (nothing is printed out when I send something to it's serial port). Here is my code (part of it at least that deals with the serial part)

Code:

DEFINE OSC 20 DEFINE HSER_TXSTA 24h DEFINE HSER_RCSTA 90h DEFINE HSER_BAUD 19200 DEFINE HSER_SPBRG 64 ' 19200 Bauds DEFINE HSER_CLROERR 1 RCIF VAR PIR1.5 ' Alias RCIF (USART Receive Interrupt Flag) OERR VAR RCSTA.1 ' Alias OERR (USART Overrun Error Flag) CREN VAR RCSTA.4 ' Alias CREN (USART Continuous Receive Enable) LED VAR PORTD.0 ' Alias LED to PORTD.0 buffer_size CON 32 ' Sets the size of the ring buffer buffer VAR BYTE[buffer_size] ' Array variable for holding received characters index_in VAR BYTE ' Pointer - next empty location in buffer index_out VAR BYTE ' Pointer - location of oldest character in buffer bufchar VAR BYTE ' Stores the character retrieved from the buffer i VAR BYTE ' loop counter errflag VAR BYTE ' Holds error flags CMCON=%00000111 ' Disable Comparators TRISA=%00000000 ' PORTA all set to Output TRISB=%11111111 ' PORTB all set to Input T0CON=%00000111 ' OFF,16BIT,PRESCALE=256 ADCON0 = 0 CMCON=7 INTCON.5=1 'T0IE : TMR0 Overflow Interrupt Enable bit ON interrupt GOTO GestIntrerupts ' Deal with interrupts ReadSerial: DataRec var byte[5] : DataRec = 0 PIE1.5 = 1 ' Enable interrupt on USART While CounterA <= 70 : WEND PIE1.5 = 0 ' Disable interrupt on USART FOR COUNTERB=0 to COUNTERA SEROUT2 SerWRT,16416,[SerDATA(COUNTERB)] NEXT COUNTERB Goto ReadReadyLoop ' Subroutines Disable ' Don't check for interrupts in this section getbuf: ' move the next character in buffer to bufchar index_out = (index_out + 1) ' Increment index_out pointer (0 to 63) IF index_out > (buffer_size-1) Then index_out = 0 ' Reset pointer if outside of buffer bufchar = buffer[index_out] ' Read buffer location Return error: ' Display error message if buffer has overrun errflag = 0 ' Reset the error flag CREN = 0 ' Disable continuous receive to clear overrun flag CREN = 1 ' Enable continuous receive GoTo display ' Carry on buffer_error: errflag.1 = 1 ' Set the error flag for software ' Move pointer back to avoid corrupting the buffer. MIN insures that it ends up within the buffer. index_in = (index_in - 1) MIN (buffer_size - 1) HSerin [buffer[index_in]] ' Overwrite the last character stored (resets the interrupt flag) usart_error: errflag.0 = 1 ' Set the error flag for hardware Resume ' Return to program GestIntrerupts: IF INTCON.2 = 1 then T0CON.0 = 0 ' Disable timer TMR0L = 0 ' Reset timer TMR0H = 0 ' Reset timer TimeCount = TimeCount + 1 T0CON.0 = 1 ' Enabled timer INTCON.2 = 0 ELSE : IF RCIF = 1 THEN IF OERR Then usart_error ' Check for USART errors index_in = (index_in + 1) ' Increment index_in pointer (0 to 63) IF index_in > (buffer_size-1) Then index_in = 0 'Reset pointer if outside of buffer IF index_in = index_out Then buffer_error ' Check for buffer overrun HSerin [buffer[index_in]] ' Read USART and store character to next empty location SEROUT2 SerWRT,16416,[buffer(index_in)] SerData(CounterA)=buffer(index_in) CounterA = CounterA + 1 IF RCIF Then GestIntrerupts ' Check for another character while we're here ENDIF : ENDIF resume ENABLE

Any input is appreciated!

Code:

DISABLE before here ENABLE after your interrupt subroutine Jump over your interrupt subroutine with a Goto Main or something ON interrupt GOTO GestIntrerupts ' Deal with interrupts ReadSerial: DataRec var byte[5] : DataRec = 0 : PIE1.5 = 1 While CounterA <= 70 : WEND PIE1.5 = 0 ' Disable interrupt on USART FOR COUNTERB=0 to COUNTERA:SEROUT2 SerWRT,16416,[SerDATA(COUNTERB)]:NEXT COUNTERB Goto ReadReadyLoop Not really a good idea inside an interrupt subroutine ' Subroutines Disable ' Don't check for interrupts in this section getbuf: ' move the next character in buffer to bufchar index_out = (index_out + 1):IF index_out > (buffer_size-1) Then index_out = 0 bufchar = buffer[index_out]:Return error: errflag = 0:CREN = 0:CREN = 1:GoTo display ' Carry on buffer_error: errflag.1 = 1:index_in = (index_in - 1) MIN (buffer_size - 1):HSerin [buffer[index_in]] usart_error: errflag.0 = 1 ' Set the error flag for hardware Resume ' Return to program GestIntrerupts: IF INTCON.2 = 1 then T0CON.0 = 0:TMR0L = 0:TMR0H = 0:TimeCount = TimeCount + 1:T0CON.0 = 1:INTCON.2 = 0 ELSE COLON isn't needed but IF RCIF = 1 THEN moved to next line is needed : IF RCIF = 1 THEN IF OERR Then usart_error ' Check for USART errors index_in = (index_in + 1):IF index_in > (buffer_size-1) Then index_in = 0 IF index_in = index_out Then buffer_error ' Check for buffer overrun HSerin [buffer[index_in]]:SEROUT2 SerWRT,16416,[buffer(index_in)]:SerData(CounterA)=buffer(index_in) CounterA = CounterA + 1 IF RCIF Then GestIntrerupts ' Check for another character while we're here ENDIF : ENDIF resume ENABLE

Where is your main loop?
You're using HSerIn with interrupts. HSerIn will wait for the NEXT character into the USART receive register after the interrupt trips.
Lots of little problems with this code...rework it a bit, straighten it out, actually READ thru it from top to bottom and see how it executes, repost, and we'll work it from there...

Well how would you suggest me to do it? Should I use serin2 instead of hserin?
I need it to be a interrupt driven buffer serial read since if I send the data too quickly it just discards some data. I tried to read the date with serin, serin2 and now hserin. My only problem now is

Code:

PIE1.5 = 1 ' Enable interrupt on USART While CounterA <= 70 : WEND PIE1.5 = 0 ' Disable interrupt on USART

Quote:

Originally Posted by johnmiller

Well how would you suggest me to do it? Should I use serin2 instead of hserin?

Any one of the SerIn functions can catch data very quickly, even at 19,200 and much higher. It mostly depends on how much time you actually need to process that data once received. Like I said, re-read thru your code, figure out what you really NEED vs. what you want to do. Write down a 'quick-n-dirty' flowchart of how you want/need things to work.
What are you buffering the serial port for?
Is this a FIFO or a LIFO type buffer (probably FIFO type)?
What is the main function of the program going to be? What is this program going to do for you?

1. i don't see any PIC #
2. i don't see any config fuses.
3. I don't see any INTCON and other interrupt related registers

Fast reading of your code but it may work. now just comment out your whole ISR and toggle a led in and then clear RCIF falg by reading RCREG untill it's empty.

Is the thing work or not? If not, your baudrate, config fuses and or hardware is faulty.

Easier way, HSERIN/HSEROUT to echo your incomming data to you PC.

Is this working or not?

Well my program needs to read the data from a serial connection and than it should save that data into a string. The only problem that I have is that if the date comes too quickly the PIC just discards that data. Any ideea why is that?

Possibly because you are sending anything received back out at the same speed within the interrupt handler.

You should get in and out of the handler as quick as possible.
Then let the mainloop empty the buffer when it has time.
Preferably at a higher speed.

Also, T0CON is different than T1CON.
TMR0ON is bit 7, and bit 0 is part of the prescaler setting.
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I tried this code:

Code:

ReadSerial: DataRec var byte[5] : DataRec = 0 KP var byte : KP = 0 While CounterA <= 70 IF index_in > (buffer_size-1) Then index_in = 0 'Reset pointer if outside of buffer HSerin [buffer[index_in]] ' Read USART and store character to next empty location if buffer(index_in) = $20 then index_in = 0 for CounterB=0 to buffer_size buffer(CounterB) = 0 next CounterB KP = 1 ENDIF if ((KP = 1) AND (index_in=4)) THEN SerData(CounterA)=buffer(4) CounterA = CounterA + 1 KP = 1 ENDIF index_in = index_in + 1 WEND

and it still doesn't work any ideea why.

PS: Is it better than the old one?

Code:

@ DEVICE PIC16F628A , HS_OSC , WDT_OFF , PWRT_ON , MCLR_ON , BOD_ON , LVP_OFF , PROTECT_OFF 'HS 20mhz external, watchdog off, powerup timer on, mclr external, brown out detect on, low volt program off , code protect off resetplaceholder: 'wordpad, arial black, size 8, reg, 1600x1200 screen, 16f628A code DEFINE OSC 20 '20mhz serdata var byte : serialbuffer var byte[255] : bufferpointer var byte bufferdata var byte : temp var byte startupholder: goto skipsubs 'skip over all the commonly used subroutines ON INTERRUPT GOTO INTHANDLER DISABLE INTERRUPT INTHANDLER: if pir1.5 = 1 then 'if serial data rx'd serdata = rcreg 'save serial port data right away pir1.5 = 0 'reset the RX flag if ( rcsta.1 = 1 ) or ( rcsta.2 = 1 ) then 'check for err, if frame/overrun error, rcsta.4 = 0 : rcsta.4 = 1 : serdata = rcreg : serdata = 0 else if bufferpointer = 255 then goto intfinish 'buffer is full serialbuffer[bufferpointer] = serdata : bufferpointer = bufferpointer + 1 'save data in buffer, bump pointer goto INTHANDLER 're-check serial port just in case another character came in while saving data '...not likely endif endif intfinish: RESUME ENABLE INTERRUPT getcharacterfrombuffer: if bufferpointer = 0 then return 'no data in buffer in the first place! buffereddata = serialbuffer[0] 'get oldest data from buffer for temp = 0 to 254 : serialbuffer[temp] = serialbuffer[temp+1] : next temp 'shift data down one byte serialbuffer[255]=0 'set last byte in buffer to zero since it's meaningless bufferpointer = bufferpointer - 1 'one less byte in buffer return skipsubs: option_reg=8 : pie1=32 : trisa=0 : porta=0 : trisb=$ef : portb=16 : t1con=0 : t2con=0 cmcon=7 : ccp1con=0 : vrcon=0 : txsta=0 : rcsta=$90 : pir1.5=0 : spbrg=33 : intcon=$e0 '9600 baud for temp = 0 to 255 : serialbuffer[temp] = 0 : next temp mainloop: goto mainloop 'do it all over again END

I modified one of my old programs. This works for me, always has.
I've left the character handling and the modifications of the program to you to make work for your PIC.

I tried your code, and now I tried the one above and still does not work

Code:

ReadSerial: DataRec var byte[5] : DataRec = 0 While CounterA <= 55 HSERIN [serdata2] 'save serial port data right away if serdata2 = $13 THEN i = 0 KP = 1 ENDIF if KP = 1 then IF i=5 THEN SerData(CounterA) = serdata2 CounterA = CounterA + 1 KP = 0 endif i = i + 1 endif wend FOR COUNTERB=42 to COUNTERA SEROUT2 SerWRT,16416,[hex2 SerDATA(COUNTERB), 10, 13] NEXT COUNTERB Goto ReadReadyLoop

I tried this one as well and it doesn't work either:

Code:

SERIN2 [WAIT($20), SKIP 4, serdata2]

PS: it doesn't work it's like the pic is not reading the data fast enough. It is supposed to read the data from a keyboard that than sends data over a serial link at 19200 (not inverted).

All the above codes work if I press a key once per second or so, but they don't work any faster. Anybody can tell me why

I think I can reasonably assume that what you posted isn't all of your code that you are trying to make work.
And if it is...well, where's the beef?
Post the whole thing if you want any useful help...

Well this is the only part where I have problems and I don't think pasting 80 pages will do any good :D
I really don't understand what's wrong with my code

Quote:

Originally Posted by johnmiller

I don't think pasting 80 pages will do any good :D
I really don't understand what's wrong with my code

And I guess neither will we...

here's the plan... shrink the whole thing and test with a simple program... simple main loop (led blinking or else) + USART INT. Then post the whole new thing.

Ok. I managed to do my work with this ;) (after a lot of struggle) but it works. Hope this code will help somebody in the future

PS: Thanks guys for the help

Code:

ReadSerial: DataRec var byte[6] for counterB=0 to 5 DataRec(counterB)=0 next counterB While CounterA <= 254 HSERIN [serdata2] DataRec(0)=DataRec(1) DataRec(1)=DataRec(2) DataRec(2)=DataRec(3) DataRec(3)=DataRec(4) DataRec(4)=DataRec(5) DataRec(5)=serdata2 IF DataRec(0)=$20 AND DataRec(2)="K" AND DataRec(3) = "E" AND DataRec(4) = "Y" THEN ' Parse serial data (command entered) SerData(CounterA) = serdata2 CounterA = CounterA + 1 endif wend FOR COUNTERB=0 to COUNTERA SEROUT2 SerWRT,16416,[SerDATA(COUNTERB), 10, 13] NEXT COUNTERB Goto MainLoop

;) While / Wend was in the bug list right? ;)

Seems good to me.