DT_Ints w/18F26K22 stop if incorrect baud rate

[Dave]

Has any body had an issue with DT-INTs and any of the new18F26K22 or similar devices? I have a program that compiles just fine and run's on an 18F26K22 with both comm ports active. When ever you send a character that is at the wrong baudrate the DT_INT's package stops all together. Even the timer interrupts. I found this when I would log off with a terminal program running on a particular pc which would leave the RS-232 line in what looks like an active state. I would restart the PIC and all would be good, even though the RS-232 line was still in the active state. I found this would only happen if the RX pin of the PIC went to the active state any longer than the selected baudrate character time. I also checked it at a much higher baudrate and found the same results. I looked to see if there were any ERRATA sheets for the 18F26K22 speaking of this problem, and there were none. The only ERRATA for the device is if using anything other than High Baud and 16 bit baud the usart might occasionally miss a start bit time. Any help would be greatly appreciated.....

[Dave]

I just did some more testing and it seems to also halt if the baudrate is incorrect on either comm port. I placed a bit toggle inside of the timer interrupt routine, another inside of each of the Usart receive interrupt routines and ALL stop if the baudrate of the incomming data on either USART is incorrect.....

[Charles Linquis]

Do you have the Clear Overflow Error defined?

(DEFINE HSER_CLROERR 1)

[Dave]

Charles, Thanks for the reply, No I have not as I have never used the commands for HSEROUT or HSERIN to do my serial activities. I ahve always used interrupts. I used to use an old set of interrupt routines originally written by Tim Box but for the last few years I have used the DT_INT routines as they seem more stable. I have as a few of the first lines in my interrupt routine a check for the overflow bit being set. There is no interrupt for the overflow bit being set. It is up to the operator to check this bit and clear it if it is set. If it IS set there will still be an interrupt generated for the RXREG having data in it. If it IS set then after reading the data in the buffer and NOT resetting it you will NOT receive any more data into the RX shift register. The problem I am having is that ALL interrupts are comming to a halt if there is an over run. It doesn't matter which USART you are using. I have the same code working on an 18F2620 with out the second USART and have NEVER had this problem.

[Dave]

Well as it goes, I found my problem. It seemed to me to be a possible stack issue the way it was acting. Sooooo, I took another longggggg look at the interrupt routines and much to my dismay, I found a few remnants of the OLD Tim Box style syntax. He used to use a RETURN when the interrupt was to be exited. Well I found one in each of the USART interrupt routines as an early exit I used at the time before I modified them to use the DT_INT's. So it was a stack issue after all. It only goes to show, If you are going to cut and paste, Make darn sure you look at it REAL GOOD before you use it. This is the second time in a couple of years this same thing has happened to me since I switched over to the DT_INT's but, I will never go back....

[Mike2545]

I know this is an old thread but I am trying to get the DT_INTS to work with the 18F26k22, so far no luck with either RX1 or RX2,the program will not jump to the label in the ASM macro

        INCLUDE "modedefs.bas"
        INCLUDE"ALLDIGITAL.pbp"
        INCLUDE "HomeAutomationVars.bas"  'Open with PBP editor
        INCLUDE "DT_INTS-18.bas"     ; Base Interrupt System
        INCLUDE "ReEnterPBP-18.bas"     ; Include if using PBP interrupts

    DEFINE PULSIN_MAX 1000
    DEFINE HSER_RCSTA 90h   'Hser receive status init
    DEFINE HSER_TXSTA 24h   'Hser transmit status init
    DEFINE HSER_BAUD 9600  'Hser baud rate
    DEFINE HSER_SPBRG 25
    DEFINE HSER_CLROERR 1
    DEFINE RX2_INT   PIR4,RC2IF, PIE4,RC2IE
    DEFINE TX2_INT   PIR4,TX2IF, PIE4,TXIE
    DEFINE DEBUG_REG PORTB  
    DEFINE DEBUG_BIT 0
    DEFINE DEBUG_BAUD 9600 
    ' Set Debug mode: 0 = true, 1 = inverted
    DEFINE DEBUG_MODE 1
    x var word
    
    Main:
    debug "here",cr
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    RX_INT,    _read_serial,   PBP,  yes
        

   endm
    INT_CREATE             ; Creates the interrupt processor
ENDASM    
T0CON = %10010010 
@   INT_ENABLE   RX_INT     ; enable external (RX) interrupts    
    
    
    for x = 1 to 1000
     pause 1
     next x

    Goto main
    
    
read_serial:
Debug "got it!!",cr    
pause 1000
goto main

Is there a fuse bit that I need to set? I had no problems with an 18F1320


Mike