Multiple PICs on usart network
Hi,
This is what my circuit looks like:
- The 18F4550 sends 1 byte to the slaves on Master TX line.
- Both slaves receive the byte properly.
- 1st slave replies successfully with same byte on Master RX line.
Problem: communication is blocked if 2nd slave is added on Master RX line.
Note: 2nd slave does not reply to master yet, extra address byte will be added later so each slave will reply only when spoken to.
Master:
Code:' 184550 external oscillator 20MHz ' 4K7 pull-up on RX @ __CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L @ __CONFIG _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H @ __CONFIG _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_1_2L & _VREGEN_ON_2L @ __CONFIG _CONFIG2H, _WDT_OFF_2H @ __CONFIG _CONFIG3H, _CCP2MX_OFF_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_ON_3H @ __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L DEFINE OSC 48 ADCON1 = %00001111 INTCON2 = %10000000 TRISA = %00000000 TRISB = %00000000 TRISC = %11000000 TRISD = %00000000 TRISE = %00000000 DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0 DEFINE HSER_CLROERR 1 ' Clear overflow automatically DEFINE HSER_SPBRG 25 ' 115200 Baud @ 48MHz, 0,16% SPBRGH = 0 BAUDCON.3 = 1 ' Enable 16 bit baudrate generator DEFINE LCD_DREG PORTD ' Set LCD data port DEFINE LCD_DBIT 0 ' Set starting data bit DEFINE LCD_BITS 8 ' Set LCD bus size DEFINE LCD_LINES 2 ' Set number of lines on LCD DEFINE LCD_RSREG PORTC ' Set LCD register select port DEFINE LCD_RSBIT 1 ' Set LCD register select bit DEFINE LCD_EREG PORTC ' Set LCD enable port DEFINE LCD_EBIT 0 ' Set LCD enable bit define LCD_COMMANDUS 1500 ' Set command delay time in microseconds DEFINE LCD_DATAUS 50 ' Set data delay time in microseconds DataIn VAR byte DataOut VAR byte low PORTC.2 Start: Pause 2000 Main: DataOut = PortC.2 LCDOUT $FE,$80,"This is the data out: ", dec1 DataOut hserout [dec1 DataOut] hSERIN [dec1 DataIn] LCDOUT $FE,$C0,"This is the data in: ", dec1 DataIn pause 1000 toggle PortC.2 GOTO Main end
1st slave:
Code:' 18F44K22 internal oscillator 64MHz ' 4K7 pull-up on RX @ __CONFIG _CONFIG1H, _FOSC_INTIO67_1H & _PLLCFG_ON_1H & _PRICLKEN_OFF_1H & _FCMEN_OFF_1H & _IESO_OFF_1H @ __CONFIG _CONFIG2L, _PWRTEN_ON_2L & _BOREN_SBORDIS_2L & _BORV_285_2L @ __CONFIG _CONFIG2H, _WDTEN_OFF_2H @ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _HFOFST_OFF_3H & _MCLRE_EXTMCLR_3H @ __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L DEFINE OSC 64 OSCCON = %01110000 OSCCON2 = %10000000 OSCTUNE = %11000000 INTCON2 = %10000000 ANSELA = 0 ANSELB = 0 ANSELC = 0 ANSELD = 0 ANSELE = 0 TRISA = %00001111 ' Set port A pins 0-3 to input, others output TRISB = %00000000 ' Set port B pins to output TRISC = %11111111 ' Set port C pins to input TRISD = %00111111 ' Set port D pins 0-5 to input, others output TRISE = %00000000 ' Set port E pins to output DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1 DEFINE HSER_CLROERR 1 ' Clear overflow automatically DEFINE HSER_SPBRG 138 ' 115200 Baud @ 64MHz, -0,08% SPBRGH = 0 BAUDCON.3 = 1 ' Enable 16 bit baudrate generator INCLUDE "DT_INTS-18.bas" ; Base Interrupt System INCLUDE "ReEnterPBP-18.bas" ; PBP Re-entry for external interrupt INCLUDE "Elapsed_INT-18.bas" ; Elapsed Timer Routines ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler RX1_INT, _ReceiveInterrupt, PBP, no endm INT_CREATE ; Creates the interrupt processor ENDASM DataIn VAR byte DataOut VAR byte RS232Flag VAR byte goto Start ReceiveInterrupt: hSERIN [dec1 DataIn] RS232Flag = 1 @ INT_RETURN Start: Pause 1500 @ INT_ENABLE RX1_INT mainloop: if RS232Flag = 1 then RS232Flag = 0 PortA.4 = DataIn DataOut = DataIn hserout [dec1 DataOut] endif Goto mainloop end
2nd slave:
This has been driving me nuts for several days. I've trimmed my programs down to this bare essential and I still can't see what I'm doing wrong.Code:' 18F26K22 internal oscillator 64MHz ' 4K7 pull-up on RX @ __CONFIG _CONFIG1H, _FOSC_INTIO67_1H & _PLLCFG_ON_1H & _PRICLKEN_OFF_1H & _FCMEN_OFF_1H & _IESO_OFF_1H @ __CONFIG _CONFIG2L, _PWRTEN_ON_2L & _BOREN_SBORDIS_2L & _BORV_285_2L @ __CONFIG _CONFIG2H, _WDTEN_OFF_2H @ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _HFOFST_OFF_3H & _MCLRE_EXTMCLR_3H @ __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L DEFINE OSC 64 OSCCON = %01110000 OSCCON2 = %10000000 OSCTUNE = %11000000 INTCON2 = %10000000 ANSELA = 0 ' Digital I/O ANSELB = 0 ANSELC = 0 TRISA = %00111111 ' Set port A pins 0-5 to input TRISB = %00000000 ' Set port B pins to output TRISC = %11000000 ' Set port C pins 6-7 to input, others output DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1 DEFINE HSER_CLROERR 1 ' Clear overflow automatically DEFINE HSER_SPBRG 138 ' 115200 Baud @ 64MHz, -0,08% SPBRGH = 0 BAUDCON.3 = 1 ' Enable 16 bit baudrate generator INCLUDE "DT_INTS-18.bas" ; Base Interrupt System INCLUDE "ReEnterPBP-18.bas" ; PBP Re-entry for external interrupt INCLUDE "Elapsed_INT-18.bas" ; Elapsed Timer Routines ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler RX1_INT, _ReceiveInterrupt, PBP, no endm INT_CREATE ; Creates the interrupt processor ENDASM DataIn VAR byte RS232Flag VAR byte RS232Flag = 0 goto Start ' Jump over sub-routines ReceiveInterrupt: ' [USART RX - interrupt handler] hSERIN 50,No232,[dec1 DataIn] RS232Flag = 1 No232: @ INT_RETURN Start: Pause 1500 @ INT_ENABLE RX1_INT ; Enable USART Receive interrupts mainloop: if RS232Flag = 1 then RS232Flag = 0 PortA.7 = DataIn endif Goto mainloop end
Everything works beautifully as long as I don't add that 2nd slave on the reply line.
Robert
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