From 2b50c3c8e3a0f3807356b7b57de950d7d0c8f233 Mon Sep 17 00:00:00 2001
From: Samuel Tardieu <sam@rfc1149.net>
Date: Thu, 11 Jul 2024 18:33:52 +0200
Subject: [PATCH] dtoverlay instructions

---
 INSTALL.md | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/INSTALL.md b/INSTALL.md
index 7d678a0..c1a589a 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -17,6 +17,12 @@ $ cargo run --release -p dc-motor-driver-hat
 
 ## Raspberry Pi
 
-On the Raspberry Pi, ensure that `boot/config.txt` contains the line `dtparam=i2c_arm=on,i2c_arm_baudrate=400000`. It is important not to let the default 100kHz speed which causes some bit flipping because of a hardware bug in the BCM2712 SOC with regard to clock stretching.
+On the Raspberry Pi, ensure that `boot/config.txt` contains the following line which defines a software I²C bus:
+
+```txt
+dtoverlay=i2c-gpio,i2c_gpio_sda=2,i2c_gpio_scl=3,bus=8
+```
+
+Ensure that the line `dtparam=i2c_arm=on` is not present: that would activate the hardware I²C bus, which cannot be used due to a hardware bug in the BCM2712 SOC with regard to clock stretching.
 
 The Python module is located in `controller/python/controller.py`.
-- 
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