Revision 0:e546fd169f96, committed 2014-08-18

Comitter:

emarin

Date:

Mon Aug 18 13:04:41 2014 +0000

Commit message:

default

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS1Wire.cpp	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,65 @@
+#include "DS1Wire.h"
+#include "mbed.h"
+#include <stdint.h>
+
+// Timing delay for 1-wire serial standard option
+enum DELAY { A = 5, B = 70, C = 70, D = 5, E = 10, F = 53, G = 0, H = 480, I = 70, J = 410 };
+
+int Reset(DigitalInOut& pin)
+{
+    pin.output();
+    pin = 0;    // drive bus low
+    wait_us(H);
+    pin.input(); // release bus
+    wait_us(I);
+    uint32_t result = pin;  // read bus value
+    wait_us(J);
+    return result;
+}
+
+void WriteBit(DigitalInOut& pin, uint32_t bit)
+{
+    if (bit) {
+        pin = 0;        // drive bus low
+        pin.output();
+        wait_us(A);        // delay A
+        pin.input();      // release bus
+        wait_us(B);        // delay B
+    } else {
+        pin = 0;    // drive bus low
+        pin.output();
+        wait_us(C);    // delay C
+        pin.input();  // release bus
+        wait_us(D);    // delay D
+    }
+}
+
+uint32_t ReadBit(DigitalInOut& pin)
+{
+    uint32_t bit_value;
+    pin.output();
+    pin = 0;        // drive bus low
+    wait_us(A);        // delay A
+    pin.input();      // release bus
+    wait_us(E);        // delay E
+    bit_value  = pin;    // master sample bus
+    wait_us(F);
+    return bit_value;
+}
+
+void WriteByte(DigitalInOut& pin, uint32_t byte)
+{
+    for (uint32_t bit = 0; bit < 8; ++bit) {
+        WriteBit(pin, byte & 0x01); // lsb to msb
+        byte >>= 1;    // right shift by 1-bit
+    }
+}
+
+uint32_t ReadByte(DigitalInOut& pin)
+{
+    uint32_t byte = 0;
+    for (uint32_t bit = 0; bit < 8; ++bit) {
+        byte |= (ReadBit(pin) << bit);    // Reads lsb to msb
+    }
+    return byte;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS1Wire.h	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,15 @@
+#ifndef __DS_1_WIRE__
+#define __DS_1_WIRE__
+#include <stdint.h>
+#include "mbed.h"
+
+int Reset(DigitalInOut& pin);
+
+void WriteBit(DigitalInOut& pin, uint32_t bit);
+uint32_t ReadBit(DigitalInOut& pin);
+
+void WriteByte(DigitalInOut& pin, uint32_t byte);
+uint32_t ReadByte(DigitalInOut& pin);
+
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX31820.cpp	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,114 @@
+#include "MAX31820.h"
+#include "DS1Wire.h"
+#include "mbed.h"
+#include <stdint.h>
+
+DigitalOut conversionInProgress(LED2);  		// conversion in progress
+DigitalOut resetFailure(LED3);          		// for error reporting
+extern DigitalInOut sensor;     				// sensor connected to pin 
+
+static void inError()
+{
+    while (1) {
+        resetFailure = !resetFailure;
+        wait(0.2);
+    }
+}
+
+ROM_Code_t ReadROM()
+{
+    ROM_Code_t ROM_Code;
+    if (Reset(sensor) != 0) {
+        inError();
+    } else {
+        WriteByte(sensor, READ_ROM);    		// Read ROM
+        for (uint32_t i = 0; i < 8; ++i) {
+            ROM_Code.rom[i] = ReadByte(sensor);
+        }
+    }
+    return ROM_Code;
+}
+
+void setResolution(uint8_t resln)
+{
+	uint32_t config = 0;
+    config |= (resln << 5);
+    WriteByte(sensor, WRITE_SCRATCHPAD);
+    WriteByte(sensor, TH_ALARM);
+    WriteByte(sensor, TL_ALARM);
+    WriteByte(sensor, config);
+    Reset(sensor);
+    WriteByte(sensor, SKIP_ROM);				// Skip ROM
+    WriteByte(sensor, COPY_SCRATCHPAD);
+    wait_ms(15);
+}
+
+void DoConversion()
+{
+    if (Reset(sensor) != 0) {
+        inError();
+    } else {
+        conversionInProgress = 1;       		// led on
+        WriteByte(sensor, SKIP_ROM);            // Skip ROM
+        WriteByte(sensor, CONVERT);				// Convert
+        while (ReadBit(sensor) == 0) {
+            // wait for conversion to complete
+        }
+        wait(1);
+        conversionInProgress = 0;       		// led off
+    }
+}
+
+float calculateTemperature(ScratchPad_t *lecture)
+{
+    uint32_t read_temp = ((lecture->MSB << 8) | lecture->LSB);;
+    bool signBit = false;
+    if (lecture->MSB & 0x80)
+        signBit = true;
+    if (signBit) {
+        read_temp = (read_temp ^ 0xFFFF) + 1;    // two's complement
+        read_temp *= -1;
+    }
+    uint32_t resolution = (lecture->config & 0x60) >> 5; // mask off bits 6,5 and move to 1,0
+    switch (resolution) {
+        case NINE_BITS:    // 0.5 deg C increments
+            read_temp &= 0xFFF8;                	// bits 2,1,0 are undefined
+            break;
+        case TEN_BITS:     // 0.25 deg C increments
+            read_temp &= 0xFFFC;                	// bits 1,0 are undefined
+            break;
+        case ELEVEN_BITS:  // 0.125 deg C increments
+            read_temp &= 0xFFFE;                	// bit 0 is undefined
+            break;
+        case TWELVE_BITS:  // 0.0625 deg C increments
+            break;
+    }
+    float realTemp = (float)read_temp/16 ;
+    return realTemp;
+}
+
+float GetTemperature()
+{
+    float temperature = 0;
+    if (Reset(sensor) != 0) {
+        inError();
+    } else {
+        ScratchPad_t dataPad;
+        WriteByte(sensor, SKIP_ROM);    		// Skip ROM
+        WriteByte(sensor, READ_SCRATCHPAD);		// Read Scrachpad
+        dataPad.LSB = ReadByte(sensor);
+        dataPad.MSB = ReadByte(sensor);
+		Reset(sensor);
+		
+        temperature = calculateTemperature(&dataPad);
+    }
+    return temperature;
+}
+
+void displayTemperature(Serial& screen)
+{
+    DoConversion();
+    float temp = GetTemperature();
+    screen.printf("\n\rTemp is %2.1f\n\r", temp);    // display in 2.1 format
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX31820.h	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,49 @@
+#ifndef _MAX31820_
+#define _MAX31820_
+
+#include <stdint.h>
+#include "mbed.h"
+
+#define	DEVICE				0x28
+#define SCRATCHPAD_SIZE		9
+#define TH_ALARM			0x7D	// 125ºC
+#define TL_ALARM			0xC9	// -50ºC
+
+// Device byte commands over 1-wire serial
+enum COMMANDS { READ_ROM = 0x33, CONVERT = 0x44, READ_SCRATCHPAD = 0xBE,
+                SKIP_ROM = 0xCC, WRITE_SCRATCHPAD = 0x4E, COPY_SCRATCHPAD = 0x48, MATCH_ROM = 0x55
+              };
+
+// Temperature read resolutions
+enum RESOLUTION {NINE_BITS , TEN_BITS, ELEVEN_BITS, TWELVE_BITS};
+
+// Device Faimly ID and Setial number information
+typedef union {
+    uint8_t rom[8];
+    struct {
+        uint8_t    familyCode;
+        uint8_t    serialNo[6];
+        uint8_t    CRC;
+    } BYTES;
+} ROM_Code_t;
+
+ROM_Code_t ReadROM() ;
+
+// device onboard register layout
+typedef struct {
+    uint8_t    LSB;
+    uint8_t    MSB;
+    uint8_t    TH;
+    uint8_t    TL;
+    uint8_t    config;
+    uint8_t    reserved0xFF;
+    uint8_t    reserved0xCH;
+    uint8_t    reserved0x10;
+    uint8_t    CRC;
+} ScratchPad_t;
+
+// Display temperature
+void displayTemperature(Serial& screen) ;
+void setResolution(uint8_t resln);
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,61 @@
+#include <mbed.h>
+#include <stdint.h>
+#include "MAX31820.h"
+
+
+extern "C" void $Sub$$SystemInit(void)
+{
+// 	System clock to the IOCON & the SWM need to be enabled or
+// 	most of the I/O related peripherals won't work. 
+    LPC_SYSCON->SYSAHBCLKCTRL |= ( (0x1 << 7) | (0x1 << 18) );
+    LPC_IOCON->PIO0_8 &= ~(0x3 << 3);				/* remove the pull-up and pull-down resistors	*/
+    LPC_IOCON->PIO0_9 &= ~(0x3 << 3);
+    LPC_SWM->PINENABLE0 &= ~(0x3 << 4);
+    LPC_SYSCON->PDRUNCFG     &= ~(0x1 << 5);        /* Power-up System Osc      */
+    LPC_SYSCON->SYSOSCCTRL    = 0x00;
+    for (uint8_t i = 0; i < 200; i++) __NOP();
+
+    LPC_SYSCON->SYSPLLCLKSEL  = 0x01;               /* Select PLL Input         */
+    LPC_SYSCON->SYSPLLCLKUEN  = 0x01;               /* Update Clock Source      */
+    while (!(LPC_SYSCON->SYSPLLCLKUEN & 0x01));     /* Wait Until Updated       */
+
+
+    LPC_SYSCON->SYSPLLCTRL    = 0x00000023;         /* P=2 (6:5), M=4 (4:0)-> 48MHz*/
+    LPC_SYSCON->PDRUNCFG     &= ~(0x1 << 7);        /* Power-up SYSPLL          */
+    while (!(LPC_SYSCON->SYSPLLSTAT & 0x01));       /* Wait Until PLL Locked    */
+
+    LPC_SYSCON->MAINCLKSEL    = 0x03;               /* Select PLL Clock Output  */
+    LPC_SYSCON->MAINCLKUEN    = 0x01;               /* Update MCLK Clock Source */
+    while (!(LPC_SYSCON->MAINCLKUEN & 0x01));       /* Wait Until Updated       */
+
+    LPC_SYSCON->SYSAHBCLKDIV  = 0x01;
+}
+
+DigitalInOut sensor(P0_7);     						/* sensor connected to pin 7	*/
+
+int main(){
+    SystemCoreClockUpdate();
+    Serial pc(USBTX, USBRX);     					/* serial comms over usb back to console	*/
+	sensor.mode(PullUp);
+
+    pc.printf("\n\r=====================================================\n\r");
+    pc.printf("MAX31820 Configuration\n\r");
+    printf("LPC812 SystemCoreClock = %d Hz\n\r", SystemCoreClock);
+
+    ROM_Code_t ROM_Code = ReadROM();
+    setResolution(TWELVE_BITS);
+
+    pc.printf("Family code: 0x%X\n\r", ROM_Code.BYTES.familyCode);
+    pc.printf("Serial Number: ");
+    for (uint32_t i = 6; i != 0; --i) {
+        pc.printf("%02X%s", ROM_Code.BYTES.serialNo[i-1], (i != 1)?":":"\r\n");
+    }
+    pc.printf("CRC: 0x%X\r\n", ROM_Code.BYTES.CRC);
+    pc.printf("\n\rRunning temperature conversion...\n\r");
+
+    while (1) {
+        displayTemperature(pc);
+        wait(2);
+    }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Aug 18 13:04:41 2014 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/9327015d4013
\ No newline at end of file