I'm new to PICs, and to get myself started I built the JMD serial PIC programmer, but when I try to program a 16F84A PIC, I get the error "Verify failed at address 0000h !".
I think i've tracked the problem to the programming voltage. During programming, the _MCLR pin is only at 6.3v.
I'm new to PICs, and to get myself started I built the JMD serial PIC programmer, but when I try to program a 16F84A PIC, I get the error "Verify failed at address 0000h !".
I think i've tracked the problem to the programming voltage. During programming, the _MCLR pin is only at 6.3v.
Either use a 'proper' serial port programmer, although these are the most expensive ones!, or search the internet for varients on the JDM programmer - there are lOAD'S of sites with improved versions, basically providing it with a proper power supply.
If you're using a laptop that could well explain your problem, the JDM programmer relies on the computer having an above spec serial port, and laptops are usually way below RS232 spec.
6.3V is seriously low, you need to measure between MCLR and the pic's ground connection (pin 5). not to the Pc's ground.
If you realy have only 6.3V that would mean your pc's serial port output is between -3 and +3 volt, no pc has that low values.
Also try measuring the serial port's voltage without the programmer connected. If it is much higher then +3 / -3V then there's probably an error in your programmer wich pulls the ports voltage down.