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Cam Bruce
Joined: 08 Sep 2003
Posts: 8
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| Write_EEPROM and RDA interrupt conflict. |
 Posted: Mon Jan 24, 2005 2:19 pm |
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My problem is an unexplainable disabling of the serial interrupt.
Using a 18F452, PCH 3.152
I have a host computer polling one register in EEPROM. The PIC receives this poll, and replies with the register value. The register value changes, repending on an Input Logic level. I think that I hit a snag, when the poll ocurrs as the input pin changes state.
At that time, I no longer get the serial interrupt.
I added LEDs to the code, so I could see. The program enters, and leaves the ISR, but, once a conflict ocurrs, the serial interrupt is disabled.
The attached code still conflicts. I have thinned it out, to try to find the problem.
Any thoughts ?
Thanks
Cam
| Code: |
////////////////////////////////////////////////////////////////////////////
//// TMB_452-13Jan05.C ////
//// Thinned out, to find why Serial Interrupt is being Disabled. ////
////////////////////////////////////////////////////////////////////////////
#include "18F452.H"
//// Definitions ////
#DEFINE DIGIN1 PIN_D1 //PIN FOR DIGITAL INPUT 1
#DEFINE FULL_RESET PIN_B1 //RESET RELAY, OUTPUT PIN
#use standard_io(C)
#DEFINE DIG_MASK 0XF4 //DIGITAL ALARM DISABLE MASK
short check_alarm=0; //used to set how long between alarm checks.
INT DIG_AMIOK; //BIT BY BIT (FOR 6 BITS) DIGITAL "AM I OK?"
INT LAST_DIG=0xFF; //THIS IS THE LAST ALARMS I HAD.
long silent_time; //used for a "long idle time" reset.
long int_count=0; // Number of interrupts left before a second has elapsed
int SECONDS=0; //a running real time counter. starts at 0 on reset, counts forever.
short from_host=0; //set in Serial ISR, while Host is sending
int byte_count=0; //counter for received numbers
int RMC_data_in[8]; //Array for data received from Host.
#byte porta=5 //These lines define the Ports.
#byte portb=6
#byte portc=7
#byte portd=8
#byte porte=9
//// End of Definitions ////
#fuses HS,NOPROTECT,NOWDT,PUT,NOLVP //WDT disabled for testing, NEEDS re-enabled
#use delay(clock=4000000) //USING A 4MHz CRYSTAL
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, parity=n)
////////////////////////////////////////////////////////////
//// THE NEXT LINES ARE THE Rx Data INTERRUPT ROUTINE. ////
#int_rda
VOID serial_isr()
{
if(kbhit()) //is there a serial byte ready ?
{
output_high(pin_d5); //turn on a LED for testing
RMC_data_in[byte_count]=getc(); //save data to the array
Silent_Time=0; //reset silent time counter
if(++byte_count>=6) //ARRAY NOW HAS THE 6 BYTE MODBUS COMMAND (use >=, to catch a runaway)
{byte_count=0; // Buffer full, RESET IT
from_host=1; //set flag, to check the string
}//end if byte_count==6
output_low(pin_d5); //turn off the LED
}
}
//// END OF INTERRUPT SERVICE ROUTINE ////
////////////////////////////////////////////////////////////
VOID main() //
{
output_low(full_reset); //don't do it.....
int_count=1; //Initialize to roll over next time through.
set_timer0(0);
setup_timer_0( RTCC_INTERNAL|rtcc_8_bit|rtcc_div_2);
SETUP_WDT(WDT_OFF); //DISABLED FOR TESTING
ENABLE_INTERRUPTS(INT_RDA); //RDA (Serial Receive Data).
enable_interrupts(global);
////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////
DO
{
if(--int_count==0) //has one second gone by ?
{
if(++SECONDS==60) //start again after one minute.
SECONDS=0;
int_count=10000; //Trial and error, 500-low,1000-low,5000-low,10000
CHECK_ALARM=1; //check alarms every second
}//end of --int count==0
if(check_alarm) //has one second gone by?
{//// Check the Digital Input Pin.
DIG_AMIOK=0xFF; //INITIALISE, ASSUMING NO ALARMS
IF(!INPUT(DIGIN1)) //CLECK EACH DIGITAL INPUT, ONE AT A TIME.
{
BIT_CLEAR(DIG_AMIOK,1); //This is for real, CLEAR THE ALARM BIT.
}
Else BIT_SET(DIG_AMIOK,1); //No alarm on input 1.
Check_Alarm=0; //reset flag
}//end of check_alarm
if((dig_amiok!=LAST_DIG)) //check for change of state in alarms
{
Write_EEPROM(0XD8,DIG_AMIOK); //FORCE A SAVE
LAST_DIG=DIG_AMIOK;
}
//////////////////////////////////////////////////////////////////////////////////////////
if(from_host) //from_host is a flag, set in the serial interrupt routine.
//by now, the array RMC_Data_In[] holds the 6 byte ModBus string.
{
output_high(pin_d6); //turn on a LED for testing
if(RMC_data_in[1]==3) //is this a "Read Register Function"?
{
if(RMC_data_in[2]==0) //"TRUE" EEPROM Area
{
putc(0x55); //repeat site address
putc(0x03); //repeat command (0x03)
putc(0x02); //number of bytes to follow
putc(0x00); //Low Byte Filler
putc(read_eeprom(RMC_Data_In[3])); //actual data from eeprom.
}//End of TRUE EEPROM Reads
}//End of all "READS"
output_low(pin_d6); //turn off the LED
from_host=0; //re-set flag.
}//END OF IF FROM_HOST...
/////////////////////////////////////////////////////////////////////////////////////
//// not much happening...
if(++silent_time>1000) //count, while waiting for another Serial Byte
{
silent_time=0; //reset silent serial time timer
byte_count=0; //reset byte counter. Clears a Runt.
}//end of silent_time>1000
}WHILE (TRUE); //"DO" IT ALL AGAIN.
} //end of Main.
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 24, 2005 2:34 pm |
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Without examining your code in detail, I can think of a number
of reasons for this:
1. You could be getting several incoming characters in a short time.
The eeprom write takes several milliseconds. You're not servicing
the interrupt during that time, so an overrun occurs. You don't
have the ERRORS directive in your #use rs232 statement, so the
USART receiver locks up.
2. In some versions of the compiler, CCS didn't handle disabling/
enabling interrupts properly during writes to eeprom. |
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Nandus2000
Joined: 17 Sep 2008
Posts: 10
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| Write_EEPROM and RDA interrupt conflict |
| Posted: Wed Jul 08, 2009 4:54 am |
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Hi,
I've used #use rs232 statement in my code.
But still I've similar issue because I'm not able to serve RS232 RDA interrupt as program is busy in write_eeprom library function.
I'm using Compiler: CCS version 4.076.
Does anybody know that this conflict has been resolved in the latest version 4.093 at the moment?
Awating your prompt reply.
Thanks!! |
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