lucalizaranzu/Shmingo-HAL
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I2C tested, main file now contains rough sample for use with DHT20

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Ea-r-th
2025-09-18 01:19:03 -07:00
parent 8ce717033a
commit cb232ea55e
4 changed files with 77 additions and 55 deletions
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46
SHAL/Src/main.cpp
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@@ -1,6 +1,7 @@
#include "SHAL.h"
#include "stm32f0xx.h"
#include <stdlib.h>
void c3Interrupt(){
SHAL_UART2.sendString("Begin\r\n");
@@ -8,35 +9,36 @@ void c3Interrupt(){
uint8_t cmd[3] = {0xAC, 0x33, 0x00};
SHAL_I2C1.masterWrite(0x38, cmd, 3);
SHAL_UART2.sendString("Hello\r\n");
SHAL_delay_ms(100);
uint8_t buffer[7] = {0};
SHAL_UART2.sendString("Buffer created?\r\n");
uint8_t dht_buf[7] = {0};
//Read 7 bytes (status + 5 data + CRC)
SHAL_I2C1.masterRead(0x38, buffer, 7);
SHAL_UART2.sendString("Read complete\r\n");
SHAL_I2C1.masterRead(0x38, dht_buf, 7);
//Parse humidity (20 bits)
uint32_t rawHumidity = ((uint32_t)buffer[1] << 12) |
((uint32_t)buffer[2] << 4) |
((uint32_t)buffer[3] >> 4);
uint32_t rawHumidity = ((uint32_t)dht_buf[1] << 12) |
((uint32_t)dht_buf[2] << 4) |
((uint32_t)dht_buf[3] >> 4);
// Parse temperature (20 bits)
uint32_t rawTemp = (((uint32_t)buffer[3] & 0x0F) << 16) |
((uint32_t)buffer[4] << 8) |
((uint32_t)buffer[5]);
uint32_t rawTemp = (((uint32_t)dht_buf[3] & 0x0F) << 16) |
((uint32_t)dht_buf[4] << 8) |
((uint32_t)dht_buf[5]);
float humidity = (rawHumidity * 100.0f) / 1048576.0f; // 2^20 = 1048576
float temperature = (rawTemp * 200.0f) / 1048576.0f - 50.0f;
// Use 64-bit intermediate to avoid overflow
uint32_t hum_hundredths = (uint32_t)(((uint64_t)rawHumidity * 10000ULL) >> 20);
int32_t temp_hundredths = (int32_t)((((uint64_t)rawTemp * 20000ULL) >> 20) - 5000);
char buf[64];
sprintf(buf, "Temp: %.2f C, Hum: %.2f %%\r\n", temperature, humidity);
SHAL_UART2.sendString(buf);
char out[80];
sprintf(out, "rawH=0x%05lX rawT=0x%05lX\r\n",
(unsigned long)rawHumidity, (unsigned long)rawTemp);
SHAL_UART2.sendString(out);
// print as X.YY
sprintf(out, "Temp: %ld.%02ld C, Hum: %ld.%02ld %%\r\n",
(long)(temp_hundredths / 100), (long)(abs(temp_hundredths % 100)),
(long)(hum_hundredths / 100), (long)(hum_hundredths % 100));
SHAL_UART2.sendString(out);
}
void tim2Handler(){
@@ -77,6 +79,10 @@ int main() {
sprintf(statusString, "Status = 0x%02X\r\n", status);
SHAL_UART2.sendString(statusString);
SHAL_delay_ms(10);
c3Interrupt();
//End setup
while (true) {