PCB Connector and Option Header pins
DC1 is a 12V input that uses a 2.1mm center pin, 5.5mm barrel plug for your external 12V supply that normally goes to the radio. Its power supplies DC2 on the front panel which powers the radio.
DSUB1 is a 15-pin high density D-Sub female connector, often called a VGA connector.
Pins 1-6 are Band outputs
Pins 7-12 are PTT outputs
Pin 13 is 24V from connector J3 if used
Pin 14 is 12V limited by a resettable 1A fuse, F1
Pin 15 is GND
J6 is an optional 1/8" stereo headphone jack. The tip and sleeve are accessed by labeled pads on the PCB next to the connector. They have no defined purpose today, but I envisioned them in use for a USB to analog CI-V bridge.
J3 is an optional 4-pin right angle header socket connector that supplies 12V on Pin 1 (left side) and accepts 24V on pin 4 (right side). Pins 2 and 3 are GND. Meant for an external DC-DC converter or 24V supply. Power is routed to the 15-pin cable to power 24v relays if you use those. Current should be limited to 1-2A, constrained by trace, header pin, and the DB15 wire sizes.
DC2 is a 12V output that uses a 2.1mm center pin, 5.5mm barrel plug. It supplies 12V to the radio.
J2 is a phono (aka RCA) jack for PTT input from the SEND output of the radio. The radio side tip connects to the PTT jack center pin. Radio side sleeve connects to the PTT jack sleeve.
There are 2 USB Type-C connectors on the front, both mounted on the ESP32-S3-DevKitC board. The one on the left is labeled USB on the DevKit board, is programmed to be a USB Host port and connects to the radio with a short USB cord, Type-C on both ends. You may want to ensure your cord is a fairly flexible cable, some of these are quite stiff straining the connectors. The USB on the right labeled COM on the CPU module connects to a PC for programming and debugging, or to pass through CI-V to a PC if the firmware is compiled for that feature.
J1 is wired to pins 8 and 9 and intended for i2c comms to optional components such as an OLED display.
Pin 1 is GND, labeled on the board on the right side
Pin 2 is CPU pin 9
Pin 3 is CPU pin 8
Pin 4 is +3.3V from the CPU is labeled on the board on the left side
J5 is for TTL level hardware serial communications options. It is the same serial data lines on the COM UART-USB port. This could be used for bridging CI-V between USB and analog in the future. J5 is next to J1 in the picture above and is oriented 180 degrees from J1 so the pins are now
Pin 1 is GND, left side
Pin 2 is CPU pin Rx
Pin 3 is CPU pin Tx
Pin 4 is +3.3V from the CPU the right side
J4 is used to optionally connect the pair of ULN2803 chips common to either 12V or 24V. These clamp the inputs to the chosen power supply voltage protecting against transients. If you have outputs connected to multiple voltage devices, select the highest voltage option, or you can leave it disconnected. If you have it connected to a 24V device, and the header is selecting 12V, then 24V will try to power the 12V, usually nothing good comes from that. When in doubt, leave it open. If connecting to relays you should use a diode across their coil terminals.
I forgot to put silkscreen labels on this board so you will want to refer here and the drawings for how to use these pins.
12V and the optional 24V power for the remote board and its loads are normally supplied by J2 pin 3 and pin 4 which comes from the radio end of the control cable. If you need more capacity then you can provide 12 and/or 24V locally. The board has 3-pin option header to select either 12V or 24V power for the 5V regulator. I specified a LM78L05 5V regulator that technically can handle 30V but if using 24V board power, verify it does not overheat and if so, use a higher rated regulator. The 78L05 is a low power part rated for 100ma. It is meant to only supply the logic chips on the boards. You can use higher capacity regulators if needed that fit the same footprint.
Here J1 selects between 12 and 24V to power the 5V regulator.
DC2 is an optional 12VDC supply for the board's 5V regulator and 12V loads. It uses a standard 2.1mm x 5.5mm barrel plug. It is tied to J2 pin 3 and the loads via J3 pin 1 through a 1A resettable fuse F1. You can opt to use J3 pin 1 as a 12V input instead if you did not bring in 12V on the input connector J2 pin3.
J2 - Input connector. This presents 12V, optional 24V, GND, and 3-line BCD signals to select 1 of the 8 buffered outputs. These inputs are buffered with weak pullups to 5VDC and are designed for 3V to 5V drive. You can install resistors in R1-R4 for higher drive voltages. R1-R4 are normally jumpered with wire. There are diodes at each input protecting them from voltages > 5V. With the 1K resistor network installed, current for each input when grounded is 5ma.
Pins left to right are:
8 - PTT
7 - Band C
6 - Band B
5 - Band A
4 - 24VDC
3 - 12VDC
2 - GND
1 - GND
J3 - Band Outputs and 12V. Outputs are open collector, 500ma max each, with a total chip load of 600ma.
Pins from left to right are:
10 - BAND_AUX2. Not normally used since the 905 USB band decoder by default uses only 6 outputs. This board may be used for general purposes, or the 905 USB controller may be custom configured to use all 8.
9 - BAND_AUX1. Not normally used since the 905 USB band decoder by default uses only 6 outputs. This board may be used for general purposes, or the 905 USB controller may be custom configured to use all 8.
8 - BAND_10G
7 - BAND_5600
6 - BAND_2300
5 - BAND_1200
4 - BAND_430
3 - BAND_144
2 - GND
1 - 24V via Fuse F2
J4 - PTT Outputs and 24V. Outputs are open collector, 500ma max each, with a total chip load of 600ma.
Pins from left to right are:
10 - PTT_AUX2. Not normally used since the 905 USB band decoder by default uses only 6 outputs. This board may be used for general purposes, or the 905 USB controller may be custom configured to use all 8.
9 - PTT_AUX1. Not normally used since the 905 USB band decoder by default uses only 6 outputs. This board may be used for general purposes, or the 905 USB controller may be custom configured to use all 8.
8 - PTT_10G
7 - PTT_5600
6 - PTT_2300
5 - PTT_1200
4 - PTT_430
3 - PTT_144
2 - GND
1 - 24V via Fuse F2
J1 - 12 or 24V power select for the onboard 5V regulator
Pin 1 - Short to pin 2 for 24V supply
Pin 2 - supply to the 5V regulator
Pin 3 - Short to Pin 2 for 12V supply. It is closest to the green terminal block connectors
J5 - Selects power supply to clamp U2 (PTT) outputs.
Pin 1 - Short to pin 2 for 24V supply
Pin 2 - Common on U2
Pin 3 - Short to Pin 2 for 12V supply. It is closest to the green terminal block connectors
J6 - Selects power supply to clamp U3 (BAND) outputs.
Pin 1 - Short to pin 2 for 24V supply
Pin 2 - Common on U3
Pin 3 - Short to Pin 2 for 12V supply. It is closest to the green terminal block connectors
