From ee8847a5886ada70d50cb0198d38c7a4cf300f97 Mon Sep 17 00:00:00 2001 From: Maurice Makaay Date: Sat, 1 May 2021 16:49:53 +0200 Subject: [PATCH] Upgrade status of the GPIO2 debug pad. As I found out by just trying it out, the debug pad for GPIO2 can be used for I/O purposes. I managed to hook up a microwave presence sensor to the debug pad, with great success. The documentation is updated with that new knowledge. --- doc/technical_details.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/doc/technical_details.md b/doc/technical_details.md index c0c7ee0..2909e57 100644 --- a/doc/technical_details.md +++ b/doc/technical_details.md @@ -83,7 +83,7 @@ pins that are not in use and their possible use. | 32 | GPIO7 | SPI | SPI flash memory | - | | 33 | GPIO8 | SPI | SPI flash memory | - | | 21 | GPIO15 | - | | IN/OUT (2) | -| 22 | GPIO2 | ??? | Debug pad, unknown function | IN/OUT (3) | +| 22 | GPIO2 | - | Debug pad, no function | IN/OUT (3) | | 23 | GPIO0 | Boot mode | Pull to GND for flashing mode | - | | 24 | GPIO4 | LEDs | LEDs, master switch 2 | - | | 25 | GPIO16 | Front pnl | Front panel interrupt | - | @@ -105,9 +105,10 @@ pins that are not in use and their possible use. repurpose it, then please let me know. 1. Beware that GPIO15 outputs a PWM signal at boot. This might make the pin less useful for your use case. -1. Often, GPIO2 is used for an on-board LED, but it looks like it is only - connected to the debug pad here. I think the pin is usable, and that it - might only be used for testing purposes in the original firmware. +1. Often, GPIO2 is used for an on-board LED. Here, it is only connected + to the debug pad. The pin is usable for I/O (I tested it), which is great + because of the easy access of the debug pad. GPIO2 might only be used for + testing purposes in the original firmware. 1. The connected IC, using I2C address 0x10, looks a lot like an EEPROM, but this has yet to be confirmed. It uses a decicated I2C bus, separate from the I2C bus of the front panel.