Nigel tut1_2 with 16F628A

hi

i am going through the tutorials on nigel site but im abit lost on the fues values to use, im using a 16F628A chip as i couldt get any 16F628

i set it to __config 0x3F1C which i worked out from the datasheet, but pins 3 & 4 are not giving an output (staying low) where all other pins are going high and low fine (port B works fine all ro und)

pin 3 is RA4/TOCKI/CMP2
ping 4 is RA5/MACLR/Vpp

i tryed 0x211C as fuse but it gives me an ID fuse error

data sheet here https://www.electro-tech-online.com/custompdfs/2005/04/40044b.pdf

thx for help
robert

kud0s said:

hi

i am going through the tutorials on nigel site but im abit lost on the fues values to use, im using a 16F628A chip as i couldt get any 16F628

i set it to __config 0x3F1C which i worked out from the datasheet, but pins 3 & 4 are not giving an output (staying low) where all other pins are going high and low fine (port B works fine all ro und)

pin 3 is RA4/TOCKI/CMP2
ping 4 is RA5/MACLR/Vpp

i tryed 0x211C as fuse but it gives me an ID fuse error

Click to expand...

RA4 is an open collector output, so it can't go HIGH - if you need it to you have to add an external pull-up resistor.

RA5 is the reset (MCLR) pin, you have to select it to be I/O in the fuse settings.

I make 0x2118 the correct value for the 628A.

I presume you're not using WinPicProg as your programming software?, so try selecting MCLR as an I/O pin in whatever programmer you use?.

Nigel Goodwin said:

kud0s said:

hi

i am going through the tutorials on nigel site but im abit lost on the fues values to use, im using a 16F628A chip as i couldt get any 16F628

i set it to __config 0x3F1C which i worked out from the datasheet, but pins 3 & 4 are not giving an output (staying low) where all other pins are going high and low fine (port B works fine all ro und)

pin 3 is RA4/TOCKI/CMP2
ping 4 is RA5/MACLR/Vpp

i tryed 0x211C as fuse but it gives me an ID fuse error

Click to expand...

RA4 is an open collector output, so it can't go HIGH - if you need it to you have to add an external pull-up resistor.

RA5 is the reset (MCLR) pin, you have to select it to be I/O in the fuse settings.

I make 0x2118 the correct value for the 628A.

I presume you're not using WinPicProg as your programming software?, so try selecting MCLR as an I/O pin in whatever programmer you use?.

Click to expand...

Don't forget that RA5/MCLR is input only!

what does open collector mean?

Gaston said:

what does open collector mean?

Click to expand...

Open colector output is "missing" a transistor to U+. Therefore it can only ground (put LOG.0) the PIN. If you want to use it as CMOS compatible output, you have to add extra resistor (4K7 )to VDD.
Open your datasheet and have a look at RA4 pin diagram, you will see why..

try connecting the led on positive supply with 1k resistor .one end of the resistor to +5v other end to led anode and leds cathode to pin 4.
. then it will work i tried doing it practically and it worked.
hope it helps u too
byee
amit

got it working thx everyone spaed a pullup resistor in the RA4 line and working now, should seen that RA5 was input only on datasheet, DOH


thx