---
active: false
created: 2025-04-29 08:16
tags:
  - eg
  - project
---
S## Goal

Create an RPi puzzle breakout board that makes it easier to plug in different switches, RFID readers and I2C components with connector pins holes aligned with red/yellow/black wires on commonly available leads.

![[Pasted image 20240618071431.png]]

Pin 1 on GPIO connector goes to Pin 1 on the breakout board.

![[GPIO_Board_v3.jpg]]
## J9

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image%20(3).png)
![[Ribbon_Cable_Orientation.png.png]]
## U1 Chip Output

We use a [CD4051B](https://www.ti.com/lit/ds/symlink/cd4051b.pdf) multiplexer chip to turn 3 GPIO lines (17, 27, 22) into 8 output control lines.  The chip's INH (disable pin) is permanently held low.  GPIO 20 provides the X input value (high or low depending the use case)

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image.png)

| Socket | Socket Pin | BCM | Pin | Action                                 |
| ------ | ---------- | --- | --- | -------------------------------------- |
| X      | 3          | 20  | 38  | Master enable switch (0 = off, 1 = on) |
| A      | 11         | 17  | 11  | Refer to selector table                |
| B      | 10         | 27  | 13  | Refer to selector table                |
| C      | 9          | 22  | 15  | Refer to selector table                |

### Selector table U1

| Reset | RSTn | A (BCM 17) | B (BCM 27) | C (BCM 22) |
| ----- | ---- | ---------- | ---------- | ---------- |
| J1    | 0    | 0          | 0          | 0          |
| J2    | 1    | 1          | 0          | 0          |
| J3    | 2    | 0          | 1          | 0          |
| J4    | 3    | 1          | 1          | 0          |
| J5    | 4    | 0          | 0          | 1          |
| J6    | 5    | 1          | 0          | 1          |
| J7    | 6    | 0          | 1          | 1          |
| J8    | 7    | 1          | 1          | 1          |

## J1 to J8

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image%20(2).png)

| Socket | Socket Pin | BCM | Pin | Action        |
| ------ | ---------- | --- | --- | ------------- |
| Jn     | 1          | 8   | 24  | SDA/SPI0/CE0  |
|        | 2          | 11  | 23  | SCK           |
|        | 3          | 10  | 19  | MOSI          |
|        | 4          | 9   | 21  | MISO          |
|        | 5          |     |     | Not connected |
|        | 6          |     | 25  | Ground        |
| J2     | 7          |     |     | See U1 table  |
| J3     | 7          |     |     | See U1 table  |
| J4     | 7          |     |     | See U1 table  |
| J5     | 7          |     |     | See U1 table  |
| J6     | 7          |     |     | See U1 table  |
| J7     | 7          |     |     | See U1 table  |
| J8     | 7          |     |     | See U1 table  |
| Jn     | 8          |     | 17  | 3V3           |

## J17 to J22

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image%20(6).png)

| Socket | Socket Pin | BCM | Pin | Action      | Position |
| ------ | ---------- | --- | --- | ----------- | -------- |
| J22    | 1          |     | 9   | Ground      |          |
|        | 2          | 25  | 22  | I/O         |          |
| J21    | 1          |     | 9   | Ground      |          |
|        | 2          | 18  | 12  | I/O<br>PWM0 |          |
| J20    | 1          |     | 9   | Ground      |          |
|        | 2          | 23  | 16  | I/O         |          |
| J19    | 1          |     | 9   | Ground      |          |
|        | 2          | 24  | 18  | I/O         |          |
| J18    | 1          |     | 9   | Ground      |          |
|        | 2          | 12  | 32  | I/O<br>PWM0 |          |
| J17    | 1          |     | 9   | Ground      |          |
|        | 2          | 16  | 36  | I/O         |          |

## J10 to J15

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image%20(4).png)

| Socket | Socket Pin | BCM | Pin | Action      |
| ------ | ---------- | --- | --- | ----------- |
| J10    | 1          | 5   | 29  | I/O         |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |
| J11    | 1          | 6   | 31  | I/O         |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |
| J12    | 1          | 13  | 33  | I/O<br>PWM1 |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |
| J13    | 1          | 19  | 35  | I/O<br>PWM1 |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |
| J14    | 1          | 26  | 37  | I/O         |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |
| J15    | 1          | 21  | 40  | I/O         |
|        | 2          |     | 39  | Ground      |
|        | 3          |     | 1   | 3V3         |

## J16

![Image.png](Attachments/Puzzle%20Breakout%20Board.assets/Image%20(5).png)

| Socket | Socket Pin | BCM | Pin | Action     | Wire Color |
| ------ | ---------- | --- | --- | ---------- | ---------- |
| J16    | 1          |     | 9   | Ground     | Black      |
|        | 2          |     | 1   | 3V3        | Red        |
|        | 3          | 3   | 5   | SCL1 / I2C | White      |
|        | 4          | 2   | 3   | SDA1 / I2C | Yellow     |

