Richard Kadrmas
/
Nucleo_i2c_mcp9808
Test Adafruit MCP9808 on i2c using Nucleo STM32F103
Revision 1:404c34e19f93, committed 2015-03-02
- Comitter:
- rkadrmas
- Date:
- Mon Mar 02 20:12:10 2015 +0000
- Parent:
- 0:41f53df528da
- Commit message:
- Nucleo F103 testing Adafruit MCP9808 on i2c at address 0
Changed in this revision
main.cpp | Show annotated file Show diff for this revision Revisions of this file |
mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
diff -r 41f53df528da -r 404c34e19f93 main.cpp --- a/main.cpp Fri Feb 21 13:02:09 2014 +0000 +++ b/main.cpp Mon Mar 02 20:12:10 2015 +0000 @@ -1,8 +1,10 @@ #include "mbed.h" - -#define LM75_REG_TEMP (0x00) // Temperature Register -#define LM75_REG_CONF (0x01) // Configuration Register -#define LM75_ADDR (0x90) // LM75 address +#include "I2C.h" + +/* MCP9808 high accuracy temp sensor from adafruit (no address pins pulled up) */ +#define MCP9808_REG_TEMP (0x05) // Temperature Register +#define MCP9808_REG_CONF (0x01) // Configuration Register +#define MCP9808_ADDR (0x30) // MCP9808 base address 0x18<<1 I2C i2c(I2C_SDA, I2C_SCL); @@ -10,59 +12,91 @@ Serial pc(SERIAL_TX, SERIAL_RX); -volatile char TempCelsiusDisplay[] = "+abc.d C"; +volatile char TempCelsiusDisplay[] = "+abc.dd C"; int main() { - char data_write[2]; + char data_write[3]; char data_read[2]; - - /* Configure the Temperature sensor device STLM75: - - Thermostat mode Interrupt + int tempval; + + wait(3); + pc.printf("PumpHouse mcp9808 test! March 2, 2015 1450\n\r"); + i2c.frequency(10000); // default is 100000 + + /* Configure the Temperature sensor device MCP9808: + - Thermostat mode Interrupt not used - Fault tolerance: 0 */ - data_write[0] = LM75_REG_CONF; - data_write[1] = 0x02; - int status = i2c.write(LM75_ADDR, data_write, 2, 0); + data_write[0] = MCP9808_REG_CONF; + data_write[1] = 0x00; // config msb + data_write[2] = 0x00; // config lsb + int status = i2c.write(MCP9808_ADDR, data_write, 3, 0); if (status != 0) { // Error + pc.printf(" error status = 0x%08x\r\n", status); while (1) { myled = !myled; wait(0.2); } } + pc.printf("enter forever loop\r\n"); while (1) { // Read temperature register - data_write[0] = LM75_REG_TEMP; - i2c.write(LM75_ADDR, data_write, 1, 1); // no stop - i2c.read(LM75_ADDR, data_read, 2, 0); + data_write[0] = MCP9808_REG_TEMP; + i2c.write(MCP9808_ADDR, data_write, 1, 1); // no stop + i2c.read(MCP9808_ADDR, data_read, 2, 0); - // Calculate temperature value in Celcius - int tempval = (int)((int)data_read[0] << 8) | data_read[1]; - tempval >>= 7; - if (tempval <= 256) { + // check Ta vs Tcrit + if((data_read[0] & 0x80) == 0x80) { + pc.printf(" temp >= critical "); + } + if((data_read[0] & 0x40) == 0x40) { + pc.printf(" temp > upper limit "); + } + if((data_read[0] & 0x20) == 0x20) { + pc.printf(" temp < lower limit "); + } + if(data_read[0] & 0xE0) { + pc.printf("\r\n"); + data_read[0] = data_read[0] & 0x1F; // clear flag bits + } + if((data_read[0] & 0x10) == 0x10) { + data_read[0] = data_read[0] & 0x0F; + TempCelsiusDisplay[0] = '-'; + tempval = 256 - (data_read[0] << 4) + (data_read[1] >> 4); + } else { TempCelsiusDisplay[0] = '+'; - } else { - TempCelsiusDisplay[0] = '-'; - tempval = 512 - tempval; + tempval = (data_read[0] << 4) + (data_read[1] >> 4); } - // Decimal part (0.5°C precision) - if (tempval & 0x01) { - TempCelsiusDisplay[5] = 0x05 + 0x30; + // fractional part (0.25°C precision) + if (data_read[1] & 0x08) { + if(data_read[1] & 0x04) { + TempCelsiusDisplay[5] = '7'; + TempCelsiusDisplay[6] = '5'; + } else { + TempCelsiusDisplay[5] = '5'; + TempCelsiusDisplay[6] = '0'; + } } else { - TempCelsiusDisplay[5] = 0x00 + 0x30; + if(data_read[1] & 0x04) { + TempCelsiusDisplay[5] = '2'; + TempCelsiusDisplay[6] = '5'; + }else{ + TempCelsiusDisplay[5] = '0'; + TempCelsiusDisplay[6] = '0'; + } } // Integer part - tempval >>= 1; TempCelsiusDisplay[1] = (tempval / 100) + 0x30; TempCelsiusDisplay[2] = ((tempval % 100) / 10) + 0x30; TempCelsiusDisplay[3] = ((tempval % 100) % 10) + 0x30; // Display result - pc.printf("temp = %s\n", TempCelsiusDisplay); + pc.printf("temp = %s\r\n", TempCelsiusDisplay); myled = !myled; wait(1.0); }
diff -r 41f53df528da -r 404c34e19f93 mbed.bld --- a/mbed.bld Fri Feb 21 13:02:09 2014 +0000 +++ b/mbed.bld Mon Mar 02 20:12:10 2015 +0000 @@ -1,1 +1,1 @@ -http://mbed.org/users/mbed_official/code/mbed/builds/ed8466a608b4 \ No newline at end of file +http://mbed.org/users/mbed_official/code/mbed/builds/9ad691361fac \ No newline at end of file