From 888a5af823e524218fc9be1f4c9323705aeb1ec5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Wed, 7 Dec 2022 11:18:40 +0100
Subject: [PATCH] =?UTF-8?q?NAK=20I=C2=B2C=20write=20when=20EDID=20protecte?=
 =?UTF-8?q?d?=
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---
 main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/main.c b/main.c
index cedf44e..b85931f 100644
--- a/main.c
+++ b/main.c
@@ -580,7 +580,11 @@ void i2c(void) __interrupt(IRQ_I2C) // auto wakeup
 			I2C_DR = *(uint8_t*)(EEPROM_ADDR + i2c_addr++); // transmit selected byte
 			i2c_input_new = false; // notify we send data
 		} else { // we will receive data
-			I2C_CR2 |= I2C_CR2_ACK; // ACK next received byte
+			if (EDID_PORT->IDR.reg & EDID_PIN) { // EDID switched off
+				I2C_CR2 &= I2C_CR2_ACK; // NACK next received byte to indicate programming it disabled
+			} else {
+				I2C_CR2 |= I2C_CR2_ACK; // ACK next received byte
+			}
 			i2c_input_new = true; // notify we get data
 		}
 	}