Sorry for the delays. I haven't had the chance yet to complete the display head modification yet. This will be completed soon and I'll program the 26k22 and let you know.
@MMcLaren , What type of information are you requesting about the displays?

 

Test the circuit without decimal point LED. if it gives proper numerical value then later decimal point can be added.

 

I've modified the display head to match (no decimal points yet) and attempted to program the 26K22 with verify errors so I'm not certain that I am programming the chip correctly. I am checking over my hardware and will get another old machine with a true serial port.
I powered the chip with no action available. I will check closer to see if I have wired the chip correctly as well. From other examples using the PIC18F26K22, pin 8/19 (vss) to ground and pin 20 to +5VDC.
I noticed that the code protection bits in the configs were enabled. Would this have anything to do with the verify errors? I am under the impression that this may prevent the chip from being read and the hex dumped.

 

It doesn't cause problems for hex dumping. it only protects the chip from reading. Maybe that is why verify is failing. Discard verify. Just write hex to chip and test.

 

@MMcLaren , What type of information are you requesting about the displays?

I asked if there was a datasheet.

 

There is no datasheet for the displays. The display circuit I am working with at this time is only for testing. This circuit can be physically configured for anything like the old Nonlinear type however, I intend to fabricate the displays by hand.

 

I have successfully programmed the 26K22 however. I connected the circuit to power but am not seeing any action. I was looking at the diagram and have noticed that the collectors and emitter on the BC327 are reversed. If I remember correctly, current flow for PNP is from collector to emitter whereas NPN current flow is from emitter to collector as seen in the diagram below:



I have tested the display head and was able to bias the transistors and activate the LED's manually as the collectors are connected to +5VDC and the emitters are connected to the LED's. I have connected the 26K22 to power via pin 20 for +5VDC and pins 8/19 to ground. Pin 1 (MCLR) is connected to +5VDC through a 10K ohm resistor. In some diagram examples, Pin 1 has an inverted signal. Is this applicable? Am I seeing the diagram incorrectly? Please advise.

 

Collectors of BC327 connects to LEDs (Anodes) and emitters to +5V.

You have to put a 100 nF (0.1 uF 16V) and a 10 uF 6.3V across power pins of MCU and close to PIC power pins.

You have to use a 5V DC power supply (well filtered) for the PIC.

You have to use a 4 Mhz Crystal with two 27 pF 16V MLCC for Oscillator and connect the Oscillator to OSC1 and OSC2 pins.

If you don't have a Crystal and associated capacitors then I will compile the project to use Internal 4 MHz oscillator.

 

Collectors of BC327 connects to LEDs (Anodes) and emitters to +5V.

Understood. Reconfiguring the circuit.

You have to put a 100 nF (0.1 uF 16V) and a 10 uF 6.3V across power pins of MCU and close to PIC power pins.

I have these in place. This is necessary.

You have to use a 5V DC power supply (well filtered) for the PIC.

I am using a well regulated 5VDC power supply.

You have to use a 4 Mhz Crystal with two 27 pF 16V MLCC for Oscillator and connect the Oscillator to OSC1 and OSC2 pins.

If you don't have a Crystal and associated capacitors then I will compile the project to use Internal 4 MHz oscillator.

I do not have a 4Mhz crystal available. I had attempted to experiment with the Oscillator Selection bits and have selected incorrectly.

 

I will compile the code for Internal Oscillator 4 Mhz and send it to you.

Edit: Find the attached file. It uses Internal 8 MHz Oscillator.

 

I have reconfigured the display circuit and tested. When power is applied to the display head alone, when the BC327's are biased to ground, the LED's activate. I've checked over the circuit, but there is no action. I have the circuit connected in the following way (minus the input portion to ADC and the decimal point LED's):

 

BC327 collector connects to anodes of LEDs and emitter to +5V. How did you connect the transistors ?

 

Exactly as you have described in PLD.pdf in the zip file and according to the schematic in my previous post. BC327 emitter to +5vdc and the collector to the LED anodes.

 

Some schematic cleanup and updating.

 

I have found a fault in the display head and have corrected it. I wrote the 26k22 with Rev D of your software and it is responding however, The some things were noticed. When input is set to 0vdc, all three zero position LED's are lit but also the 9 LED in the MSD row. The center row and LSD row have various LED's that pulse with a pattern while those zero position LED's are lit. Perhaps my filtering on the power is not sufficient enough?

 

Will check the code again and post new code if there are any corrections.

 

I used the single potentiometer from the proteus diagram for simple input. It is not filtered and may be the source of spurious noise coming in. I will work to filter the input so that cleaner numbers coming in will help the results.

I noticed that when I power on the MCU, All LEDs light up and the action hangs. But if I bump the power, the MCU action begins. This gives me an indication that my power filtering may not be ideal. I'll investigate it further.

 

Test this. There is not much change. Just removed two useless instructions. Working is same as previous version. I have debugged the code with three different values viz 3.25, 32.5 and 325 and code is fine. You have to check your hardware.

 

Discard all previous files and use the attached project.

When you make the display unit send I unit to me.

Your circuit is wrong. PORTC connections are wrong. Use attached circuit.

 

Ah. My goof. 'Edge Lit Display Schematic.rar' clarifies the LED numerical sequence greatly. I will reconfigure the display circuit to follow and will update you.