Merge pull request #30 from UnifiedEngineering/max31855-integration

Add support for the sc18is602b + max31855 combo

src/main.c

@@ -34,6 +34,7 @@
 #include "buzzer.h"
 #include "nvstorage.h"
 #include "version.h"
+#include "max31855.h"
 
 extern uint8_t logobmp[];
 extern uint8_t stopbmp[];
@@ -192,6 +193,7 @@ int main(void) {
 	ADC_Init();
 	RTC_Init();
 	OneWire_Init();
+	SPI_TC_Init();
 	Reflow_Init();
 
 	Sched_SetWorkfunc( MAIN_WORK, Main_Work );

src/max31855.c

@@ -0,0 +1,118 @@
+/*
+ * max31855.c - SPI TC interface handling for T-962 reflow controller
+ *
+ * Copyright (C) 2014 Werner Johansson, wj@unifiedengineering.se
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include "sc18is602b.h"
+#include "sched.h"
+
+#define MAX_SPI_DEVICES (4)
+int16_t spidevreadout[MAX_SPI_DEVICES]; // Keeps last readout from each device
+int16_t spiextrareadout[MAX_SPI_DEVICES]; // Keeps last readout from each device
+int numspidevices = 0;
+
+static int32_t SPI_TC_Work( void ) {
+	int32_t retval;
+
+	for( int i = 0; i < numspidevices; i++ ) {
+		SPIxfer_t xfer;
+		xfer.ssmask = 1<<i;
+		xfer.len = 4; // 32 bits from TC interface
+		retval = SC18IS602B_SPI_Xfer( &xfer ); // Doesn't matter what data contains when sending, MOSI not connected
+		if( retval == 0 ) {
+			int16_t tmp = xfer.data[0]<<8 | xfer.data[1];
+			spidevreadout[i] = tmp;
+			tmp = xfer.data[2]<<8 | xfer.data[3];
+			spiextrareadout[i] = tmp;
+		}
+	}
+	return TICKS_MS(100);
+}
+
+uint32_t SPI_TC_Init( void ) {
+	printf("\n%s called",__FUNCTION__);
+	Sched_SetWorkfunc( SPI_TC_WORK, SPI_TC_Work );
+
+	for( int i = 0; i < MAX_SPI_DEVICES; i++ ) {
+		spidevreadout[i] = -1; // Assume we don't find any thermocouple interfaces
+		spiextrareadout[i] = -1;
+	}
+
+	if( SC18IS602B_Init( SPICLK_1843KHZ, SPIMODE_0, SPIORDER_MSBFIRST ) >= 0 ) { // Only continue of we find the I2C to SPI bridge chip
+		printf("\nProbing for MAX31855 devices...");
+
+		numspidevices = MAX_SPI_DEVICES; // Assume all devices are present for SPI_TC_Work
+		SPI_TC_Work(); // Run one iteration to update all data
+		numspidevices = 0; // And reset it afterwards
+
+		for( int i = 0; i < MAX_SPI_DEVICES; i++ ) {
+			if( (spidevreadout[i] == -1 && spiextrareadout[i] == -1) ||
+					(spidevreadout[i] == 0 && spiextrareadout[i] == 0) ) {
+				//printf(" Unknown/Invalid/Absent device");
+			} else {
+				printf("\nSS%x: [SPI Thermocouple interface]", i);
+				numspidevices = i + 1; // A bit of a hack as it assumes all earlier devices are present
+			}
+		}
+
+		if( numspidevices ) {
+			Sched_SetState( SPI_TC_WORK, 2, 0 ); // Enable SPI TC task if there's at least one device
+		} else {
+			printf(" No devices found!");
+		}
+	}
+	return numspidevices;
+}
+
+int SPI_IsTCPresent(uint8_t tcid) {
+	if(tcid < numspidevices) {
+		if( !(spidevreadout[tcid] & 0x01) ) return 1; // A faulty/not connected TC will not be flagged as present
+	}
+	return 0;
+}
+
+float SPI_GetTCReading(uint8_t tcid) {
+	float retval = 0.0f; // Report 0C for missing sensors
+	if(tcid < numspidevices) {
+		if(spidevreadout[tcid] & 0x01) { // Fault detected
+			retval = 999.0f; // Invalid
+		} else {
+			retval=(float)(spidevreadout[tcid] & 0xfffc); // Mask reserved bit
+			retval/=16;
+			//printf(" (%x=%.1f C)",tcid,retval);
+		}
+	}
+	return retval;
+}
+
+float SPI_GetTCColdReading(uint8_t tcid) {
+	float retval = 0.0f; // Report 0C for missing sensors
+	if(tcid < numspidevices) {
+		if(spiextrareadout[tcid] & 0x07) { // Any fault detected
+			retval = 999.0f; // Invalid
+		} else {
+			retval=(float)(spiextrareadout[tcid] & 0xfff0); // Mask reserved/fault bits
+			retval/=256;
+			//printf(" (%x=%.1f C)",tcid,retval);
+		}
+	}
+	return retval;
+}

src/max31855.h

@@ -0,0 +1,9 @@
+#ifndef MAX31855_H_
+#define MAX31855_H_
+
+uint32_t SPI_TC_Init( void );
+int SPI_IsTCPresent(uint8_t tcid);
+float SPI_GetTCReading(uint8_t tcid);
+float SPI_GetTCColdReading(uint8_t tcid);
+
+#endif /* MAX31855_H_ */

src/reflow.c

@@ -31,6 +31,7 @@
 #include "onewire.h"
 #include "adc.h"
 #include "nvstorage.h"
+#include "max31855.h"
 
 float adcgainadj[2]; // Gain adjust, this may have to be calibrated per device if factory trimmer adjustments are off
 float adcoffsetadj[2]; // Offset adjust, this will definitely have to be calibrated per device
@@ -119,7 +120,16 @@ static int32_t Reflow_Work( void ) {
 				tempvalid |= (1<<i);
 			}
 		} else {
-			//printf("TC%x=---C ",i);
+			tcpresent[i] = SPI_IsTCPresent( i );
+			if( tcpresent[i] ) {
+				tctemp[i] = SPI_GetTCReading( i );
+				tccj[i] = SPI_GetTCColdReading( i );
+				printf("TC%x=%5.1fC ",i,tctemp[i]);
+				if(i>1) {
+					temperature[i] = tctemp[i];
+					tempvalid |= (1<<i);
+				}
+			}
 		}
 	}
 	cjsensorpresent = 0; // Assume no CJ sensor

src/sc18is602b.c

@@ -0,0 +1,58 @@
+/*
+ * sc18is602b.c - I2C to SPI bridge handling for T-962 reflow controller
+ *
+ * Copyright (C) 2014 Werner Johansson, wj@unifiedengineering.se
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include "i2c.h"
+#include "sc18is602b.h"
+
+#define SCADDR (0x28<<1)
+
+int32_t SC18IS602B_Init( SPIclk_t clk, SPImode_t mode, SPIorder_t order ) {
+	uint8_t function[2];
+	int32_t retval;
+	printf("\n%s ",__FUNCTION__);
+	function[0] = 0xf0;
+	function[1] = clk | mode | order;
+	retval = I2C_Xfer(SCADDR, function, sizeof(function), 1); // Attempt to initialize I2C to SPI bridge
+	if( retval == 0 ) {
+		printf( "- Done");
+	} else {
+		printf( "- No chip found");
+	}
+	return retval;
+}
+
+int32_t SC18IS602B_SPI_Xfer( SPIxfer_t* item ) {
+	int32_t retval;
+	if( item->len > (sizeof(SPIxfer_t) - 2) ) {
+		printf("\n%s: Invalid length!",__FUNCTION__);
+		return -1;
+	}
+	retval = I2C_Xfer(SCADDR, (uint8_t*)item, item->len + 1, 1); // Initialize transfer, ssmask + data
+	if( retval == 0 ) {
+		// TODO: There should be a timeout here
+		do {
+			retval = I2C_Xfer(SCADDR + 1, (uint8_t*)item->data, item->len, 1); // Initialize read transfer, data only
+		} while( retval != 0 ); // Wait for chip to be done with transaction
+	}
+	return retval;
+}

src/sc18is602b.h

@@ -0,0 +1,32 @@
+#ifndef SC18IS602B_H_
+#define SC18IS602B_H_
+
+typedef enum eSPIclk {
+	SPICLK_1843KHZ=0,
+	SPICLK_461KHZ=1,
+	SPICLK_115KHZ=2,
+	SPICLK_58KHZ=3,
+} SPIclk_t;
+
+typedef enum eSPImode {
+	SPIMODE_0=(0<<2),
+	SPIMODE_1=(1<<2),
+	SPIMODE_2=(2<<2),
+	SPIMODE_3=(3<<2),
+} SPImode_t;
+
+typedef enum eSPIorder {
+	SPIORDER_MSBFIRST=(0<<5),
+	SPIORDER_LSBFIRST=(1<<5),
+} SPIorder_t;
+
+typedef struct __attribute__ ((__packed__)) {
+	uint8_t ssmask;
+	uint8_t data[16]; // Max 16 bytes at the moment
+	uint8_t len;
+} SPIxfer_t;
+
+int32_t SC18IS602B_Init( SPIclk_t clk, SPImode_t mode, SPIorder_t order );
+int32_t SC18IS602B_SPI_Xfer( SPIxfer_t* item );
+
+#endif /* SC18IS602B_H_ */

src/sched.h

@@ -23,6 +23,7 @@ typedef enum eTask {
 	MAIN_WORK,
 	ADC_WORK,
 	ONEWIRE_WORK,
+	SPI_TC_WORK,
 	UI_WORK,
 	REFLOW_WORK,
 	NV_WORK,