From 3eb211fb5494715aa2a5f909e8c6f5dca1a7294f Mon Sep 17 00:00:00 2001
From: true <true_git@trueserve.org>
Date: Thu, 8 Aug 2024 03:35:03 -0700
Subject: [PATCH] finally fixed bug in i2c address scan check routine

was checking if set instead of negated. oops.
---
 firmware/retro_tech_fw/user/src/i2c.c | 18 +++++++-----------
 firmware/retro_tech_fw/user/src/i2c.h |  2 +-
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/firmware/retro_tech_fw/user/src/i2c.c b/firmware/retro_tech_fw/user/src/i2c.c
index a7ec75f..fea6a44 100644
--- a/firmware/retro_tech_fw/user/src/i2c.c
+++ b/firmware/retro_tech_fw/user/src/i2c.c
@@ -80,12 +80,10 @@ int8_t i2c_read_addr1b(uint8_t addr, uint8_t reg, uint8_t *data, uint8_t len)
 
        *data++ = I2C_ReceiveData(I2C1);
        len--;
-
-       if (!len) {
-           I2C_GenerateSTOP(I2C1, ENABLE);
-       }
     }
 
+    I2C_GenerateSTOP(I2C1, ENABLE);
+
     return 0;
 }
 
@@ -145,7 +143,7 @@ void i2c_write_reg_8b(uint8_t addr, uint8_t reg, const uint8_t dat)
     i2c_write_addr1b(addr, reg, &dat, 1);
 }
 
-uint8_t i2c_addr_scan(uint8_t addr)
+int8_t i2c_addr_scan(uint8_t addr)
 {
     uint8_t found = 1;
     uint32_t event;
@@ -164,30 +162,28 @@ uint8_t i2c_addr_scan(uint8_t addr)
     while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT) && timeout--);
     if (!timeout) return -2;
 
-    I2C_Send7bitAddress(I2C1, addr, (addr & 1));
+    I2C_Send7bitAddress(I2C1, (addr & 0xfe), (addr & 0x01));
     timeout = I2C_TIMEOUT_ACK_POLL;
     if (addr & 1) event = I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED;
     else          event = I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED;
 
-    while (I2C_CheckEvent(I2C1, event) && timeout--) {
+    while ((I2C_CheckEvent(I2C1, event) == NoREADY) && timeout--) {
         if (I2C_GetFlagStatus(I2C1, I2C_FLAG_AF)) {
             found = 0;
             break;
         }
-
     }
 
     if (!timeout) {
         found = 0;
     }
 
-    // reset flags; it might be in a fucked state
-    I2C1->STAR1 = 0;
-
     // send a stop to make sure anything listening knows to stfu
     I2C_GenerateSTOP(I2C1, ENABLE);
 
+    // reset flags; it might be in a fucked state
     if (!found) {
+        I2C1->STAR1 = 0;
         return 0;
     }
 
diff --git a/firmware/retro_tech_fw/user/src/i2c.h b/firmware/retro_tech_fw/user/src/i2c.h
index 9e68ba7..7ca772c 100644
--- a/firmware/retro_tech_fw/user/src/i2c.h
+++ b/firmware/retro_tech_fw/user/src/i2c.h
@@ -19,7 +19,7 @@ int8_t i2c_write_addr1b(uint8_t addr, uint8_t reg, const uint8_t *data, uint8_t
 uint8_t i2c_read_reg_8b(uint8_t addr, uint8_t reg);
 void i2c_write_reg_8b(uint8_t addr, uint8_t reg, const uint8_t dat);
 
-uint8_t i2c_addr_scan(uint8_t addr);
+int8_t i2c_addr_scan(uint8_t addr);