From d5d784bb1a6d87b75b5064d7238a63220eed26a3 Mon Sep 17 00:00:00 2001
From: Peter Harper <peter.harper@raspberrypi.com>
Date: Mon, 18 Mar 2024 18:22:59 +0000
Subject: [PATCH 1/3] Fix reading of dig_H5 and dig_H6

Fixes #480
---
 spi/bme280_spi/bme280_spi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/spi/bme280_spi/bme280_spi.c b/spi/bme280_spi/bme280_spi.c
index c6c50b11f..457324405 100644
--- a/spi/bme280_spi/bme280_spi.c
+++ b/spi/bme280_spi/bme280_spi.c
@@ -163,15 +163,15 @@ void read_compensation_parameters() {
     dig_P8 = buffer[20] | (buffer[21] << 8);
     dig_P9 = buffer[22] | (buffer[23] << 8);
 
-    dig_H1 = buffer[25];
+    dig_H1 = buffer[25]; // 0xA1
 
     read_registers(0xE1, buffer, 8);
 
-    dig_H2 = buffer[0] | (buffer[1] << 8);
-    dig_H3 = (int8_t) buffer[2];
-    dig_H4 = buffer[3] << 4 | (buffer[4] & 0xf);
-    dig_H5 = (buffer[5] >> 4) | (buffer[6] << 4);
-    dig_H6 = (int8_t) buffer[7];
+    dig_H2 = buffer[0] | (buffer[1] << 8); // 0xE1 | 0xE2
+    dig_H3 = (int8_t) buffer[2]; // 0xE3
+    dig_H4 = buffer[3] << 4 | (buffer[4] & 0xf); // 0xE4 | 0xE5[3:0]
+    dig_H5 = (buffer[4] >> 4) | (buffer[5] << 4); // 0xE5[7:4] | 0xE6
+    dig_H6 = (int8_t) buffer[6]; // 0xE7
 }
 
 static void bme280_read_raw(int32_t *humidity, int32_t *pressure, int32_t *temperature) {

From 755f5ff369b3a250c7ecb39e8a2f65728ee7bba8 Mon Sep 17 00:00:00 2001
From: Peter Harper <peter.harper@raspberrypi.com>
Date: Mon, 18 Mar 2024 18:49:31 +0000
Subject: [PATCH 2/3] Fix reading of dig_H1

Fixes #111
---
 spi/bme280_spi/bme280_spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spi/bme280_spi/bme280_spi.c b/spi/bme280_spi/bme280_spi.c
index 457324405..eb2643bdf 100644
--- a/spi/bme280_spi/bme280_spi.c
+++ b/spi/bme280_spi/bme280_spi.c
@@ -147,7 +147,7 @@ static void read_registers(uint8_t reg, uint8_t *buf, uint16_t len) {
 void read_compensation_parameters() {
     uint8_t buffer[26];
 
-    read_registers(0x88, buffer, 24);
+    read_registers(0x88, buffer, 26);
 
     dig_T1 = buffer[0] | (buffer[1] << 8);
     dig_T2 = buffer[2] | (buffer[3] << 8);

From e3d5df34a5b1b8893e42f29cc7b06aa4301861b7 Mon Sep 17 00:00:00 2001
From: Peter Harper <peter.harper@raspberrypi.com>
Date: Mon, 18 Mar 2024 18:50:32 +0000
Subject: [PATCH 3/3] Fix order of reading of temp and pressure

Fixes #442
---
 spi/bme280_spi/bme280_spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spi/bme280_spi/bme280_spi.c b/spi/bme280_spi/bme280_spi.c
index eb2643bdf..74a4e228a 100644
--- a/spi/bme280_spi/bme280_spi.c
+++ b/spi/bme280_spi/bme280_spi.c
@@ -225,8 +225,8 @@ int main() {
 
         // These are the raw numbers from the chip, so we need to run through the
         // compensations to get human understandable numbers
-        pressure = compensate_pressure(pressure);
         temperature = compensate_temp(temperature);
+        pressure = compensate_pressure(pressure);
         humidity = compensate_humidity(humidity);
 
         printf("Humidity = %.2f%%\n", humidity / 1024.0);