Repeater GPIO Connections

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RPi 4 GPIO pin out

• Note the RPi4 (only) can be powered with 5.2 v directly on Pins 2 and 4. Ground is Pins 6, 9, 14, 20, 25, 30, 34 and 39.

GPIO Connections for the ATV Repeater

Here is the initial list of GPIO connections.

Pin No	BCM No	Wiring Pi	RPi Pri	RPi Alt0	Primary Use	Secondary Use	Notes
1	-	-	3.3v	-	Clock module	-	-
2	-	-	5v	-	-	-	-
3	2	8	GPIO 2	SDA1	Clock module	-	-
4	-	-	5v	-	-	-	-
5	3	9	GPIO 3	SCL1	Clock module	-	-
6	-	-	0v	-	-	-	-
7	4	7	GPIO 4	GPCLK0	Clock module	-	-
8	14	15	GPIO 14	TXD0	i2c sda	RS-232?	i2c needs 1k8 p/u to +3v3
9	-	-	0v	-	Clock module	-	-
10	15	16	GPIO 15	RXD0	i2c scl	RS-232?	i2c needs 1k8 p/u to +3v3
11	17	0	GPIO 17	FL1	-	IR Sensor Input?	For initial config
12	18	1	GPIO 18	-	IR Sender Output	-	To control HDMI Switch
13	27	2	GPIO 27	SD0_DAT3	IR Bank Select	-	Hi for upstream HDMI switch
14	-	-	0v	-	-	-	-
15	22	3	GPIO 22	SD0_CLK	Rack power control	-	Active high output
16	23	4	GPIO 23	SD0_CMD	RX 5 Active	-	Active high input
17	-	-	3.3v	-	-	-	-
18	24	5	GPIO 24	SD0_DAT0	RX 3 Active	-	Active high input
19	10	12	GPIO 10	SPI0_MOSI	RX 6 Active	-	Active high input
20	-	-	0v	-	-	-	-
21	9	13	GPIO 9	SPI0_MISO	RX 7 Active	Rack shutdown button	Low to toggle shutdown
22	25	6	GPIO 25	SD0_DAT1	RX 4 Acive	-	Active high input
23	11	14	GPIO 11	SPI0_SCLK	Output 6 select	Spare GPIO	Active high output
24	8	10	GPIO 8	SPI0_CE0_N	Output 7 select	Rack Shutdown signal	Active low to trigger shutdown
25	-	-	0v	-	-	-	-
26	7	11	GPIO 7	SPI0_CE1_N	Hardware Shutdown	-	Active low if enabled
27	0	30	ID_SD	SDA0	Reserved	-	Not Available
28	1	31	ID_SC	SCL0	Reserved	-	Not Available
29	5	21	GPIO 5	GPCLK0	Output 5 select	Spare GPIO	Active high output
30	-	-	0v	-	-	-	-
31	6	22	GPIO 6	GPCLK2	Output 4 select	Spare GPIO	Active high output
32	12	26	GPIO 12	PWM0	RX 1 Active	-	Active high input
33	13	23	GPIO 13	PWM1	Output 3 select	Spare GPIO	Active high output
34	-	-	0v	-	-	-	-
35	19	24	GPIO 19	SPI6_MESO	RX 2 Active	-	Active high input
36	16	27	GPIO 16	FL0	Output 0 select	Spare GPIO	Active high output
37	26	25	GPIO 26	SD0_DAT2	Output 1 select	Spare GPIO	Active high output
38	20	28	GPIO 20	SPI6_MOSI	Output 2 select	Spare GPIO	Active high output
39	-	-	0v	-	-	-	-
40	21	29	GPIO 21	SPI6_SCLK	PTT for TX	-	Active high

The clock module that may be used (not tested yet) on pins 1, 3, 5, 7 and 9 is this https://thepihut.com/blogs/raspberry-pi-tutorials/17209332-adding-a-real-time-clock-to-your-raspberry-pi. This would allow the repeater to keep track of time without an internet connection and reset correctly after power outages.

Note that the GPIO pin names are markedly different from the RPi 3B. Each pin on the RPi4 GPIO can be referred to in many ways: its physical pin number, the Broadcom I/O number, the Wiring Pi number or the primary or alternate names. Source for GPIO designations was the Raspberry Pi 4 Model B datasheet.

Functional List

Function	Pin
Receiver 1 Active	32
Receiver 2 Active	35
Receiver 3 Active	18
Receiver 4 Active	22
Receiver 5 Active	16
Receiver 6 Active	19
Receiver 7 Active	21
-	-
IR LED Drive	12
IR Bank Select	13
-	-
Transmitter PTT	40
-	-
Output 0 select	36
Output 1 select	37
Output 2 select	38
Output 3 select	33
Output 4 select	31
Output 5 select	29
Output 6 select	23
Output 7 select	24
-	-
Hardware Shutdown	26
-	-
IR Sensor	11