Hi am trying to send data from 2 sharp GP2D02 proximity sensors and 2 devantech srf04 ultrasonic sensors being controlled by a PIC16F872 through gigatechnology's usbmod2 (Serial To Usb module) to my computer. I have given the code below that I am using but unfortunately I cannot get it working. A very strange thing happens when I connect a wire between VSS pin 19 and OSC2 pin 10, once I turn on the power I pull this wire out. When I do this and check the pins on a oscilloscope I get the correct measurements for example a 10us trigger going to the srf04 and output from the GP2D02 going from low to high although I do not get the correct information into the computer. Due to this I think most of my code is correct and it may be something very small stopping the PIC from working correctly. Please help me if you can as I've been trying to get this working for weeks with no success. ; pin assignments ; portB 0-7 = USB D0-D7 normally inputs, switched to outputs when ; writing to usb ; portC.7 = output USBWR normally low - pulse high to write ; portC.6 = input USBTXF low means ok to write ; portC.5 = output USBRD normally high - pulse low to read ; portC.4 = input USBRXF low means ok to read ; portC.3 = output SRF1Trigger normally low ; portC.2 = input SRF1Echo - time high pulse following trigger ; portC.1 = output SRF2Trigger ; portC.0 = input SRF2Echo ; pulse trigger hi for 10usec to start conversion ; Echo duration 100usec to 36000usec ; divide by 58 for millimeters or 148 for inches ; range of 1(1.7) to 620 cm = 0(0.67) to 243 inches ; portA.3 = output IR1Clock pulse hi 10usec to start conversion ; portA.2 = input IR1Data - time high pulse following trigger ; portA.1 = output IR2Clock ; portA.0 = input IR2Data ; drop clock low to start conversion and wait for data ; to go high (about 70 milliseconds ; set clock high for 2 usec then low and read Data bit, ; after 2usec set clock high again ; repeat for 7 additional bits ; end with clock high. list P=16F872 #include <p16f872.inc> ;===================== ; Declaration #define USBWR PORTC,7 #define USBTXF PORTC,6 #define USBRD PORTC,5 #define USBRXF PORTC,4 #define SRF1Trigger PORTC,3 #define SRF1Echo PORTC,2 #define SRF2Trigger PORTC,1 #define SRF2Echo PORTC,0 #define USBData PORTB #define IR1Clock PORTA,3 #define IR1Data PORTA,2 #define IR2Clock PORTA,1 #define IR2Data PORTA,0 #define LED1 PORTA,5 #define LED2 PORTA,4 ;start general purpose registers N equ 0x20 ;simple counter counts 1 second periods T equ 0x21 ;counts 4 ms periods for the 1 second counter U equ 0x22 ;stores value read from USB port I equ 0x23 ;general purpose temp variable J equ 0x24 ;general purpose temp varaible org 0x0000 goto Init org 1ch Init movlw 0x10 movwf T1CON ;Timer1 - prescale 1:2, oscillator disabled, internal clock, not running, ;set for 1 usec. rate clrf INTCON ; Disable all interrupts and clear T0IF clrf PORTA ;set all outputs low clrf PORTB clrf PORTC ;except... bsf USBRD ;normally high bsf IR1Clock ;normally high bsf IR2Clock ;normally high bsf STATUS, RP0 ; Bank1 movlw 0xc4 ; PortB pull-ups are disabled movwf OPTION_REG ; Interrupt on rising edge of RB0 - interrrupts are not enabled ; Timer0 increment from internal clock ; with a prescaler of 1:16 - will count at 8usec rate. ; wdt will timeout at 18msec. movlw 0x06 movwf ADCON1 ;port A is all digital i/o - no a/d movlw b'11000101' ;1,3,4 and 5 are outputs movwf TRISA movlw b'11111111' movwf TRISB movlw b'01010101' ;1,3,5 and 7 are outputs movwf TRISC bcf STATUS, RP0 ; Bank0 bsf USBRD ;normally high bcf USBWR ;normally low bsf IR1Clock ;normally high bsf IR2Clock ;normally high bcf SRF1Trigger ;normally low bcf SRF2Trigger ;normall low clrf N ;start at 0 clrf T clrf U ;******************************************************************* ;main program loop here ;output sequence will be 0,0,SRF1Hi,SRF1Lo,IR1,SRF2Hi,SRF2Lo,IR2, repeat... ;can synchronize by waiting for two zero values in fast succession, ;less than 1ms apart Loop movlw 0 call WriteUSB movlw 0 call WriteUSB call ReadSRF1 ;returned in Timer1 - 1 to 36 ms movfw TMR1H call WriteUSB movfw TMR1L call WriteUSB call ReadIR1 ;returned in W - 70 ms call WriteUSB call ReadSRF2 ;returned in Timer1 - 1 to 36 ms movfw TMR1H call WriteUSB movfw TMR1L call WriteUSB call ReadIR2 ;returned in W - 70 ms call WriteUSB goto Loop ;******************************************************************* ReadUSB ;if USBRXF is low, read usb port to W btfsc USBRXF goto ReadUSBDone bcf USBRD ;RD low nop nop ;pause a little movf USBData,W ;data from USB movwf U ;save it in U bsf USBRD ;RD back to high ReadUSBDone return ;******************************************************************* WriteUSB ;if USBTXF is low, write W to usb port btfsc USBTXF goto WriteUSBDone ;if USBTXF is high, skip writing movwf USBData ;W to data port bsf STATUS,RP0 movlw 0x00 movwf TRISB ;data port to output mode bcf STATUS,RP0 bsf USBWR ;WR high nop ;pause just a little nop bcf USBWR ;WR low bsf STATUS,RP0 movlw 0xff movwf TRISB ;data port back to input mode bcf STATUS,RP0 WriteUSBDone return ;******************************************************************* ;Reads IR1 Sensor, returns value in W, takes about 70 milliseconds ;uses temp variables I and J ;set clock low ;wait for data to go low ;set clock high then low ;read data bit - rotate bit into J ;repeat for rest of 8 bits ;set clock high ReadIR1 bcf IR1Clock btfsc IR1Data goto $-1 ;wait for IR1Data low clrwdt ;keep watch dog happy btfss IR1Data goto $-2 ;wait for IR1Data high movlw .8 movwf I ;counter for 8 bits ReadIR1Loop bsf IR1Clock ;set clock high nop nop ;pause a little bcf IR1Clock ;set clock low nop nop ;pause a little bcf STATUS,C ;clear carry bit btfsc IR1Data bsf STATUS,C ;if data is high, set carry bit rlf J ;shift carry bit into J decfsz I goto ReadIR1Loop ;repeat for all 8 bits movfw J bsf IR1Clock ;set clock high again return ;******************************************************************* ReadIR2 bcf IR2Clock btfsc IR2Data goto $-1 ;wait for IR2Data low clrwdt ;keep watch dog happy btfss IR2Data goto $-2 ;wait for IR2Data high movlw .8 movwf I ;counter for 8 bits ReadIR2Loop bsf IR2Clock ;set clock high nop nop ;pause a little bcf IR2Clock ;set clock low nop nop ;pause a little bcf STATUS,C ;clear carry bit btfsc IR2Data bsf STATUS,C ;if data is high, set carry bit rlf J ;shift carry bit into J decfsz I goto ReadIR2Loop ;repeat for all 8 bits movfw J bsf IR2Clock ;set clock high again return ;******************************************************************* ;set SRF1Trigger high ;wait at least 10us ;set SRF1Trigger low ;wait for SRF1Echo to go high ;time until SRF1Echo goes low (100 to 36000 usec.) ReadSRF1 bsf SRF1Trigger ;set trigger high movlw .7 movwf I decfsz I goto $-1 ;delay 11.5 usec. bcf SRF1Trigger ;set trigger low bcf T1CON,0 ;stop timer1 clrf TMR1H clrf TMR1L ;and set it to zero clrwdt ;keep watch dog happy btfsc SRF1Echo goto $-2 ;wait for echo low ;echo is now high bsf T1CON,0 ;start timer1 clrwdt btfss SRF1Echo goto $-2 ;wait for echo low again bcf T1CON,0 ;stop timer1 ;timer1 contains echo pulse in usec. return ;******************************************************************* ReadSRF2 bsf SRF2Trigger ;set trigger high movlw .7 movwf I decfsz I goto $-1 ;delay 11.5 usec. bcf SRF2Trigger ;set trigger low bcf T1CON,0 ;stop timer1 clrf TMR1H clrf TMR1L ;and set it to zero clrwdt ;keep watch dog happy btfsc SRF2Echo goto $-2 ;wait for echo low ;echo is now high bsf T1CON,0 ;start timer1 clrwdt btfss SRF2Echo goto $-2 ;wait for echo low again bcf T1CON,0 ;stop timer1 ;timer1 contains echo pulse in usec. return ;******************************************************************* SetLED1 ;turns LED1 on or off according to low bit of N btfsc N,0 goto SetLED1On SetLED1Off bcf LED1 return SetLED1On bsf LED1 return ;******************************************************************* SetLED2 ;turns LED2 on or off according to low bit of U btfsc U,0 goto SetLED2On SetLED2Off bcf LED2 return SetLED2On bsf LED2 return ;******************************************************************* END
Problems with PIC167872 sending data from sensors to computer through usb module gigatechnology usbmod2
Started by ●April 7, 2004
Reply by ●April 7, 20042004-04-07
<big snip> Sounds to me like you haven't set up the config bytes for the PIC correctly. i.e. oscillator type, reset, etc etc
Reply by ●April 7, 20042004-04-07
Hi Clement, As already told, it look like the config bits are wrong. See the __CONFIG command in MPLAB help. You'll need the datasheet of that PIC also. May be you can tell your programmer manually to set the config bits. HTH Wolfgang -- From-address is Spam trap Use: wolfgang (dot) mahringer (at) sbg (dot) at
Reply by ●April 13, 20042004-04-13
Thanks a lot you were right about the configuration bits I had not turned brown out detect on and that was the problem. I am now receiving information into the computer but unfortunately it does not appear to be correct. I should first of all be receiving two zeros to help me synchronize the data, following this 1 byte for the data from infrared sensor 1, 2 bytes for ultrasonic sensor 1, 1 byte from infrared sensor 2 followed by 2 bytes for ultrasonic sensor 2. I'm not even getting the 2 zeros into the computer. If I program the PIC just to send out a zero I get 11 (oB in hex) into the computer and for 1 I get 31 (1F in hex). What do you think could be the problem? Could it be a timing issue between the PIC and the USB module? Below is the data that I am receiving at the computer with ultrasonic sensor 2 turned off as it's not working. Thanks #31#31#63#31#31#31#63#31#31#31#31#31#31#31#31#31#31#31#31#63#31#31#31#31#31#11#31#11#31#31#31#31#31#27#31#31#31#31#31#31#31#31#31#31#31#31#31#11#31#31#31#11#63#31#11#31#31#63#31#31#11#63#63#63#63#31#11#31#31#31#31#31#31#63#31#31#31#11#11#31#31#31#31#31#11#31#31#31#31#31#31#31#31#31#31#31#31#11#31#31#63#31#63#63#31#31#31#31#31#31#31#63#63#31#31#31#31#31#31#63#11#31#63#31#63#31#31#31#31#31#31#31#31# 1#31#31#31#31#11#31#31#31#31#31#11#31#31#31#31#31#31#31#31#27#31#31#31#31#63#31#31#31#31#31#31#63#31#63#31#31#27#31#31#11#31#11#31#31#31#31#31#31#31#11#31#31#31#63#31#31#31#31#31#27#31#31#31#31#31#31#31#31#31#11#11#31#31#63#31#27#31#31#31#31#63#63#31#31#31#63#31#31#11#31#31#31#63#31#31#31#31#31#31#31#31#31#31#31#31#31#31#31#31#63#31#31#11#31#31#11#31#31#63#63#31#31#31#31#31#63#31#11#31#31#31#31#31 31#31#31#31#11#31#31#31#11#11#11#31#31#31#11#31#31#31#31#31#31#63#31#31#31#31#31#31#63#31#63#63#31#31#31#11#31#31#11#31#31#31#63#11#63#31#31#27#31#31#63#31#11#31#31#31#31#31#31#31#31#31#31#11#31#31#31#31#31#31#31
Reply by ●April 14, 20042004-04-14
clement wrote:> > Thanks a lot you were right about the configuration bits I had not...snip ...> #31#31#63#31#31#31#63#31#31#31#31#31#31#31#31#31#31#31#31#63#31#31#31#31#31#11#31#11#31#31#31#31#31#27#31#31#31#31#31#31#31#31#31#31#31#31#31#11#31#31#31#11#63#31#11#31#31#63#31#31#11#63#63#63#63#31#11#31#31#31#31#31#31#63#31#31#31#11#11#31#31#31#31#31#11#31#31#31#31#31#31#31#31#31#31#31#31#11#31#31#63#31#63#63#31#31#31#31#31#31#31#63#63#31#31#31#31#31#31#63#11#31#63#31#63#31#31#31#31#31#31#31#31#What is this stupid nonsense? Get rid of it. -- Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net> USE worldnet address!
