BATC Forum

Good morning all,

I need some assistance please with my Portsdown 4 build.

I have the Raspberry PI 4 and the version 2.12 plug on GPIO breakout board, I also have the 8 band decoder PCB complete with a BATC programmed PIC.

Following the Wiki I have connected this as follows
3.3 volt from J5
Grnd, LSB, MSB, and T from J6
These are connected to the relevant pins on J1 on the 8 band decoder PCB.

I have a brand new Portsdown build on the PI and none of the LEDs will light on the band decoder PCB.

The voltage on LSB and MSB change as different bands are selected and I am seeing this on the band decoder as well.

Led polarity is correct. I have also tried changing the setting for the GPIO as per the Wiki but still no luck.

Any advice on what is not correct or a setting that I have missed?

I am beginning to wonder if the PIC has not been programmed so I need to connect up my PIC programmer and check if the PIC has any code in it.

73 Keith GU6EFB

Hello Keith,

It looks as though you have the wiring correct between the RPi 4 breakout board V2.12 (J5 and J6) and (J1) 8 Band decoder:

- J5 pin 3v3 to J1 pin 1,
- J6 pin D2 to J1 pin 5 (T),
- J6 pin D1 to J1 pin 3,
- J6 pin D0 to J1 pin 2,
- J6 pin GND to J1 pin 4 (0V) I also have:
- J6 pin 40 to J1 pin 6 (PTT).

JP1 (Bands Outputs) on the 8 band decoder PCB I have set the jumper to 'always on' see circuit diagram:

https://wiki.batc.org.uk/images/6/66/8_ ... -0_SCH.pdf

If you have fitted the switches on the 8 band decode PCB (not required) they should be turned off.

It could well be a PIC issue. Is the 8 band decoder getting 3V3?

One LED should light up after powering the P4 up if everything is working.

73 Wolfgang

Hi Wolfgang

Many thanks for the help and advice.

As the band decoder was powered from the PI as per the Wiki I had not included a 0 Volt but did have the ground connected.
Added 0 volt and all now working as expected.

Many thanks for pointing me in the right direction.

73 Keith GU6EFB