Hi Folks,
Just had a quick play with a GLCD screen, hooked it up to a 18F46K22, ran through a Simulator, all worked OK, went to program the device and thought I had a problem, turned out I needed to hook up the contrast POT, oops
Enter problem,
It may be something very simple that I am doing wrong, I have looked at several different circuits and they are all showing the same to hook the pot between vee and 0v, I tried that, and I have since hooked it up the same way the manufacturer of the GLCD (Midas) recommends which is between vee and +5v, anyway, once programmed everything works as it did on the Simulator (after swapping the CS pins around!), the problem is that with the POT in the circuit the PIC won't program properly comes up with read errors when programming, with the pot in circuit turned up to around 5v it seems to sometimes program sometimes not.
PIC is hooked up as usual, two decoupling caps, 7805 and a few more caps, 10k pull up to +5V on MCLR, ICSP wired in, as soon as I introduce the POT it comes up with programming errors, the POT is connected to Vee and +5V of the GLCD and the wiper is connected to V0 which is the contrast adjust, seems that -2.5v is around the viewing contrast for me.
What can I do to allow me to keep my contrast whilst programming? I have checked for shorts etc, all seems to be fine.
Any help appreciated!
Thanks guys, and sorry for the looong post, just wanted to be as descriptive as I can!
Kind Regards
Wilksey
Just had a quick play with a GLCD screen, hooked it up to a 18F46K22, ran through a Simulator, all worked OK, went to program the device and thought I had a problem, turned out I needed to hook up the contrast POT, oops
Enter problem,
It may be something very simple that I am doing wrong, I have looked at several different circuits and they are all showing the same to hook the pot between vee and 0v, I tried that, and I have since hooked it up the same way the manufacturer of the GLCD (Midas) recommends which is between vee and +5v, anyway, once programmed everything works as it did on the Simulator (after swapping the CS pins around!), the problem is that with the POT in the circuit the PIC won't program properly comes up with read errors when programming, with the pot in circuit turned up to around 5v it seems to sometimes program sometimes not.
PIC is hooked up as usual, two decoupling caps, 7805 and a few more caps, 10k pull up to +5V on MCLR, ICSP wired in, as soon as I introduce the POT it comes up with programming errors, the POT is connected to Vee and +5V of the GLCD and the wiper is connected to V0 which is the contrast adjust, seems that -2.5v is around the viewing contrast for me.
What can I do to allow me to keep my contrast whilst programming? I have checked for shorts etc, all seems to be fine.
Any help appreciated!
Thanks guys, and sorry for the looong post, just wanted to be as descriptive as I can!
Kind Regards
Wilksey