Help with stopping a loop with a serial receive on 16F876.
Greetings
Can any one assist me in a small problem (I think!). I have code for a 16F876, using MCS and PBP, that in one section captures CCP1 in a constant loop and sends the result out through the USART port (HERSOUT). In order to stop this looping I utilise a button press on PortA.5, but what I am looking to try and do is stop this looping code when a single character is received at the PIC USART from my PC.
I have been looking at various registers hoping for some kind of bit change that would indicate a character has just been received, but the only bit regarding receiving data seems to be PIR1.5. This though is “The USART receive buffer is full” bit, so unless I sent lots of characters I am not sure this is what I am looking for?.
A point in the right direction as where to look for an answer would be greatly appreciated.
Below is part of my code:
Many thanks and Merry Christmas.Code:DEFINE OSC 20 DEFINE ADC_BITS 10 ' Number of bits in ADCIN result DEFINE ADC_CLOCK 3 ' ADC clock source (rc = 3) DEFINE ADC_SAMPLEUS 20 ' ADC sampling time in microseconds DEFINE HSER_BAUD 115200 DEFINE HSER_CLROERR 1 ' Automatically clear over-run errors DEFINE HSER_SPBRG 10 ' 20 = 57600 . 21 may be option. 115200 = 10 DEFINE HSER_RCSTA 90h ' Enable USART receive DEFINE HSER_TXSTA 24H ' Set TXSTA to allow for higher baud rate TRISA = %11111111 ' PortA all inputs TRISC = %11111111 ' PortC all inputs ADCON1 = %10000100 ' Set PORTA analog ADCON0 = %00000001 ' Configure and turn on A/D Module PIE1.0 = 1 'enables the tmr1 overflow interrupt capture VAR PIR1.2 ' CCP1 capture flag capture2 var PIR2.0 ' CCP2 capture flag overflow VAR PIR1.0 ' Timer1 overflow flag OERR VAR RCSTA.1 ' Alias USART over-run bit CREN VAR RCSTA.4 ' Alias USART continuous receive enable bit ExhTemp var word ' AFM input AirTemp var word ' Air Temp Sensor Input period var Word ' Pulse 1 Rising edge trigger period2 var word ' Pulse 2 Rising edge trigger MI var word ' Serial Input character I var word ' Loop variable mycount var word menuselect: Hserin [MI] ' Wait for Character input to start if MI = "A" then gosub About if MI = "S" then gosub sloop if MI = "G" then gosub gratio if MI<>"A" or "S" or "G" then goto menuselect goto menuselect sloop: T1CON = %00100000 ' TMR1 prescale=1:4 Timer OFF _ %00010000 1:2 TMR1H = 0 ' Zero the Timer High TMR1L = 0 ' Zero the Timer Low capture = 0 CCP1CON = %00000110 ' Every 4th = 00000110. Every = 00000101 StartLoop: IF (capture = 0) Then StartLoop ' Wait here for the first capture T1CON.0 = 1 ' Start the Timer capture = 0 ' Reset the capture flag CaptureLoop: IF (capture = 0) Then CaptureLoop ' Wait here until captured period.lowbyte = CCPR1L ' Store the captured value in period.highbyte = CCPR1H ' period variable T1CON.0 = 0 ' Turn off Timer1 if PIR1.0 = 1 then ' Check for Timer1 overflow period2 = 65535 PIR1.0 = 0 endif Hserout [DEC5 period,DEC5 period2,"T",13,10] IF PORTA.5 = 0 THEN return ' If PORTA, pin 5 is low (0), return to menu “This where I would like to check for USART receive” period2 = 0 GoTo sloop ' Do until signal to stop or do something else
Originally Posted by Ceetee
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