I have a PIC18LF1220 in 20-pin SSOP package running at 4MHz from internal clock source and 3.3 volts. I have soldered the microcontroller onto a pcb with a groundplane on the bottom layer and the pic is on the top layer. I'm using two 0.1µF ceramic bypass capacitors one for VDD & VSS and one for AVdd & AVss pair. I also have one 10kOhm pullup resistor on the MCLR pin. I have the programming header on the board just about 3cm away from the pic and couple of the first programming on this prototype board worked fine, but after these first programming runs ICD3 says the following:
Programming... program memory Address: 0 Expected Value: 59 Received Value: 0 Failed to program device
This is the third pic chip on board that refuses to program again. I have had to change the chip every two new prototype programs as the same problem has always occured after two programming runs. Why is the pic refusing to reprogram after two previous programmings that worked fine? I had the previous program run all night to test it worked properly (just a simple pin blink program) and now it just won't do anything as it seems that the erase worked, but no new code was loaded (at least properly). This behaviour seems to be very consistent as all these three PIC's have died after trying to program them for the third time. Below is the complete message given by ICD3.
Connecting to MPLAB ICD 3... Currently loaded firmware on ICD 3 Firmware Suite Version.....01.43.35 Firmware type..............PIC18F Programmer to target power is enabled - VDD = 3,250000 volts. Target device PIC18LF1220 found. Device ID Revision = 7 The following memory area(s) will be programmed: program memory: start address = 0x0, end address = 0x74f configuration memory Device Erased... Programming... program memory Address: 0 Expected Value: 59 Received Value: 0 Failed to program device
Could it be that this particular batch I have has some flash memory issues (I have verified this problem on three pics one after another). The chips I have here are all reported to be of revision 7 silicon by the ICD3. Below are the config bits I have been using if they could have something to do with the problem (I highly doubt that they would cause this kind of problem).
// CONFIG1H #pragma config OSC = INTIO2 // Oscillator Selection bits (Internal RC oscillator, port function on RA6 and port function on RA7) #pragma config FSCM = OFF // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor enabled) #pragma config IESO = ON // Internal External Switchover bit (Internal External Switchover mode enabled) // CONFIG2L #pragma config PWRT = OFF // Power-up Timer Enable bit (PWRT disabled) #pragma config BOR = OFF // Brown-out Reset Enable bit (Brown-out Reset enabled) // BORV = No Setting // CONFIG2H #pragma config WDT = OFF // Watchdog Timer Enable bit (WDT disabled (control is placed on the SWDTEN bit)) #pragma config WDTPS = 32768 // Watchdog Timer Postscale Select bits (1:32768) // CONFIG3H #pragma config MCLRE = ON // MCLR Pin Enable bit (MCLR pin enabled, RA5 input pin disabled) // CONFIG4L #pragma config STVR = ON // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset) #pragma config LVP = OFF // Low-Voltage ICSP Enable bit (Low-Voltage ICSP disabled) // CONFIG5L #pragma config CP0 = OFF // Code Protection bit (Block 0 (00200-0007FFh) code-protected) #pragma config CP1 = OFF // Code Protection bit (Block 1 (000800-000FFFh) code-protected) // CONFIG5H #pragma config CPB = ON // Boot Block Code Protection bit (Boot Block (000000-0001FFh) code-protected) #pragma config CPD = OFF // Data EEPROM Code Protection bit (Data EEPROM not code-protected) // CONFIG6L #pragma config WRT0 = OFF // Write Protection bit (Block 0 (00200-0007FFh) not write-protected) #pragma config WRT1 = OFF // Write Protection bit (Block 1 (000800-000FFFh) not write-protected) // CONFIG6H #pragma config WRTC = OFF // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected) #pragma config WRTB = OFF // Boot Block Write Protection bit (Boot Block (000000-0001FFh) not write-protected) #pragma config WRTD = OFF // Data EEPROM Write Protection bit (Data EEPROM not write-protected) // CONFIG7L #pragma config EBTR0 = OFF // Table Read Protection bit (Block 0 (00200-0007FFh) not protected from table reads executed in other blocks) #pragma config EBTR1 = OFF // Table Read Protection bit (Block 1 (000800-000FFFh) not protected from table reads executed in other blocks) // CONFIG7H #pragma config EBTRB = OFF // Boot Block Table Read Protection bit (Boot Block (000000-0001FFh) not protected from table reads executed in other blocks)