# HG changeset patch
# User Ethan Zonca <ez@ethanzonca.com>
# Date 2015-08-23 19:04:19
# Node ID a76c60e8cc43a5ed19276fb9b732834cd16733ad
# Parent  49485c1fefaedada391805cf3110bc73030b6a6b

Add MAX31865 RTD reader stub code

diff --git a/max31865.c b/max31865.c
new file mode 100644
--- /dev/null
+++ b/max31865.c
@@ -0,0 +1,74 @@
+#include "stm32f0xx_hal.h"
+
+#include "config.h"
+#include "stringhelpers.h"
+#include "states.h"
+#include "gpio.h"
+
+// Grab temperature reading from MAX31865
+void max31865_readtemp(SPI_HandleTypeDef* hspi1, therm_settings_t* set, therm_status_t* status)
+{
+    // ** FIXME ** FIXME ** FIXME ** //
+    // This is duplicated from MAX31855, update for MAX31865 registers/etc
+    /////////////////////////////////// 
+
+    // Assert CS
+    HAL_GPIO_WritePin(MAX_CS, 0);
+
+    uint8_t rxdatah[1] = {0x00};
+    uint8_t rxdatal[1] = {0x00};
+
+    HAL_SPI_Receive(hspi1, rxdatah, 1, 100);
+    HAL_SPI_Receive(hspi1, rxdatal, 1, 100);
+
+    // Release CS
+    HAL_GPIO_WritePin(MAX_CS, 1);
+
+    // Assemble data array into one var
+    uint16_t temp_pre = rxdatal[0] | (rxdatah[0]<<8);
+    if(temp_pre & 0b001 && !set->ignore_tc_error) {
+        status->tc_errno = 1;
+        HAL_Delay(400); // FIXME: remove?
+        status->state_resume = status->state;
+        status->state = STATE_TC_ERROR;
+        status->temp = 0;
+        status->temp_frac = 0;
+    }
+    else 
+    {
+        uint8_t sign = status->temp >> 15;// top bit is sign
+        temp_pre = temp_pre >> 2; // Drop 2 lowest bits
+        status->temp_frac = temp_pre & 0b11; // get fractional part
+        status->temp_frac *= 25; // each bit is .25 a degree, up to fixed point
+        temp_pre = temp_pre >> 2; // Drop 2 fractional bits 
+
+        int8_t signint;
+
+        if(sign) {
+            signint = -1;
+        }
+        else {
+            signint = 1;
+        }
+
+        // Convert to Fahrenheit
+        if(set->temp_units == TEMP_UNITS_FAHRENHEIT)
+        {
+            status->temp = signint * ((temp_pre*100) + status->temp_frac);
+            status->temp = status->temp * 1.8;
+            status->temp += 3200;
+            status->temp_frac = status->temp % 100;
+            status->temp /= 100;
+            status->temp += set->temp_offset;
+        }
+
+        // Use Celsius values
+        else
+        {
+            status->temp = temp_pre * signint;
+            status->temp += set->temp_offset;
+        }
+    }
+}
+
+// vim:softtabstop=4 shiftwidth=4 expandtab 
diff --git a/max31865.h b/max31865.h
new file mode 100644
--- /dev/null
+++ b/max31865.h
@@ -0,0 +1,8 @@
+#ifndef MAX31865_H 
+#define MAX31865_H 
+
+void max31865_readtemp(SPI_HandleTypeDef* hspi1, therm_settings_t* set, therm_status_t* status);
+
+#endif
+
+// vim:softtabstop=4 shiftwidth=4 expandtab