Stefan Guenther
Interface Driver for Maxim DS2482 1Wire-to-I2C bridge IC. Includes access functions for DS1820 temperature sensors. Can easily be ported to other hardware by using hardware abstraction layer.
Usage Example - main.cpp
#include "mbed.h"
#include "ds2482.h"
#define MAX_TEMP_SENSORS 16
#define CONNECTED_DS2482_HUBS 2
struct sDS1820_t
{
struct sDS2482_t *hub;
uint8_t u8RomNr[8];
};
struct sDS1820_t sDS1820[MAX_TEMP_SENSORS];
struct sDS2482_t sDS2482[CONNECTED_DS2482_HUBS];
Serial console(USBTX, USBRX);
I2C i2c (p9, p10);
int8_t i8SetupTempSensors(void)
{
int x=0;
sDS2482[0].u8Addr = DS2482_ADDR1;
sDS2482[1].u8Addr = DS2482_ADDR2;
for(int loop=0; loop<2; loop++)
{
int8_t i8Tmp = i8DS2482Reset(&sDS2482[loop]);
if(i8Tmp)
return i8Tmp;
i8Tmp = i8DS2482SetControlBits(&sDS2482[loop], APU | SPU );
if(i8Tmp)
return i8Tmp;
i8Tmp = i8DS2482_OWReset(&sDS2482[loop]);
if(i8Tmp)
return i8Tmp;
while(i16DS2482_OWSearch(&sDS2482[loop]) > 0)
{
sDS1820[x].hub = &sDS2482[loop];
for(int z=0; z<8; z++)
sDS1820[x].u8RomNr[z] = sDS2482[loop].u8RomNr[z];
x++;
}
}
return x;
}
int main(void)
{
uint8_t u8SensorCount;
mbed_i2c = &i2c;
console.baud(115200);
int8_t i8Ret = i8SetupTempSensors();
if(i8Ret < 0)
{
console.printf("Error -i8Ret\n");
while(1); // error occured
}
u8SensorCount = i8Ret;
while(1)
{
// Start Temperature Conversion on all DS1820
for(uint8_t loop = 0; loop < CONNECTED_DS2482_HUBS; loop++)
{
i8Ret = i8DS2482_OWStartAllDS1820(&sDS2482[loop], 0);
if(i8Ret)
{
console.printf("Error %i\n", -i8Ret);
while(1); // error!
}
}
// Wait until all DS1820 have completed the conversion
for(uint8_t loop = 0; loop < CONNECTED_DS2482_HUBS; loop++)
while(!i8DS2482_OWCheckDeviceReady(&sDS2482[loop]));
// Get temperature values and display them
for(uint8_t z=0; z<u8SensorCount; z++)
{
int16_t i16Tmp = i16DS2482_OWReadDS1820(sDS1820[z].hub, sDS1820[z].u8RomNr, 0);
if(i16Tmp < 0)
{
console.printf("Error %i\n", -i16Tmp);
while(1); // error
}
else
{
uint8_t u8Tmp = (i16Tmp-109)/2;
uint8_t u8Tmp2;
if((int16_t)u8Tmp*2+109 != i16Tmp)
u8Tmp2=5;
else
u8Tmp2=0;
console.printf("[%02i] %02i", z+1, u8Tmp);
console.printf(",%iC | ", u8Tmp2);
}
if((z+1)%8==0)
console.printf("\n");
}
}
}
Diff: ds2482.h
- Revision:
- 0:39243a42bc87
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ds2482.h Thu Jul 24 14:14:40 2014 +0000
@@ -0,0 +1,209 @@
+#include "i2c_api.h"
+#include "wait_api.h"
+
+/* Driver Object Definition */
+struct sDS2482_t
+{
+ uint32_t u32Flags;
+ uint8_t u8Addr;
+
+ uint8_t u8RomNr[8];
+ int16_t i16LastDiscrepancy;
+ int16_t i16LastFamilyDiscrepancy;
+ int16_t i16LastDeviceFlag;
+ uint8_t u8CRC8;
+} ;
+
+/* DS2482 Low-Level-Interface */
+int8_t i8DS2482Reset (struct sDS2482_t *dev);
+int16_t i16DS2482GetStatus (struct sDS2482_t *dev);
+int8_t i8DS2482SetControlBits (struct sDS2482_t *dev, uint8_t u8Flags);
+// TODO: extract basic write/read function from higher-level functions below
+
+/* 1Wire Interface Functions */
+int8_t i8DS2482_OWWait (struct sDS2482_t *dev);
+int8_t i8DS2482_OWReset (struct sDS2482_t *dev);
+int8_t i8DS2482_OWTouchBit (struct sDS2482_t *dev, uint8_t sendbit);
+int8_t i8DS2482_OWReadBit (struct sDS2482_t *dev);
+int8_t i8DS2482_OWWriteBit (struct sDS2482_t *dev, uint8_t sendbit);
+int8_t i8DS2482_OWWriteByte (struct sDS2482_t *dev, uint8_t sendbyte);
+int16_t i16DS2482_OWReadByte (struct sDS2482_t *dev);
+int8_t i8DS2482_OWBlock (struct sDS2482_t *dev, uint8_t *tran_buf, uint8_t tran_len);
+int16_t i16DS2482_OWTouchByte (struct sDS2482_t *dev, uint8_t sendbyte);
+int16_t i16DS2482_OWFirst (struct sDS2482_t *dev);
+int16_t i16DS2482_OWNext (struct sDS2482_t *dev);
+int16_t i16DS2482_OWSearch (struct sDS2482_t *dev);
+int16_t i16DS2482_search_triplet (struct sDS2482_t *dev, int search_direction);
+int8_t i8DS2482_OWSelectDevice (struct sDS2482_t *dev, uint8_t *u8SN);
+int8_t i8DS2482_OWCheckDeviceReady (struct sDS2482_t *dev);
+
+/* DS1820-Specific High-Level-Functions */
+int8_t i8DS2482_OWStartAllDS1820 (struct sDS2482_t *dev, uint8_t u8WaitForCompletion);
+int16_t i16DS2482_OWReadDS1820 (struct sDS2482_t *dev, uint8_t *u8SN, uint8_t u8ManualStart);
+int8_t i8DS2482_OWReadDS1820Precise(struct sDS2482_t *dev, uint8_t *u8SN, uint8_t u8ManualStart, int16_t *i16Temperature);
+
+/* Helper Function */
+uint8_t calc_crc8 (uint8_t *data_in, int number_of_bytes_to_read);
+
+/* =============== USAGE EXAMPLE ===============
+#include "mbed.h"
+#include "ds2482.h"
+
+#define MAX_TEMP_SENSORS 16
+#define CONNECTED_DS2482_HUBS 2
+
+struct sDS1820_t
+{
+ struct sDS2482_t *hub;
+ uint8_t u8RomNr[8];
+};
+
+struct sDS1820_t sDS1820[MAX_TEMP_SENSORS];
+struct sDS2482_t sDS2482[CONNECTED_DS2482_HUBS];
+
+Serial console(USBTX, USBRX);
+I2C i2c (p9, p10);
+
+int8_t i8SetupTempSensors(void)
+{
+ int x=0;
+
+ sDS2482[0].u8Addr = DS2482_ADDR1;
+ sDS2482[1].u8Addr = DS2482_ADDR2;
+
+ for(int loop=0; loop<2; loop++)
+ {
+ int8_t i8Tmp = i8DS2482Reset(&sDS2482[loop]);
+ if(i8Tmp)
+ return i8Tmp;
+
+ i8Tmp = i8DS2482SetControlBits(&sDS2482[loop], APU | SPU );
+ if(i8Tmp)
+ return i8Tmp;
+
+ i8Tmp = i8DS2482_OWReset(&sDS2482[loop]);
+ if(i8Tmp)
+ return i8Tmp;
+
+ while(i16DS2482_OWSearch(&sDS2482[loop]) > 0)
+ {
+ sDS1820[x].hub = &sDS2482[loop];
+ for(int z=0; z<8; z++)
+ sDS1820[x].u8RomNr[z] = sDS2482[loop].u8RomNr[z];
+ x++;
+ }
+ }
+ return x;
+}
+
+int main(void)
+{
+ uint8_t u8SensorCount;
+
+ mbed_i2c = &i2c;
+
+ console.baud(115200);
+
+ int8_t i8Ret = i8SetupTempSensors();
+
+ if(i8Ret < 0)
+ {
+ console.printf("Error -i8Ret\n");
+ while(1); // error occured
+ }
+
+ u8SensorCount = i8Ret;
+
+ while(1)
+ {
+ // Start Temperature Conversion on all DS1820
+ for(uint8_t loop = 0; loop < CONNECTED_DS2482_HUBS; loop++)
+ {
+ i8Ret = i8DS2482_OWStartAllDS1820(&sDS2482[loop], 0);
+ if(i8Ret)
+ {
+ console.printf("Error %i\n", -i8Ret);
+ while(1); // error!
+ }
+ }
+
+ // Wait until all DS1820 have completed the conversion
+ for(uint8_t loop = 0; loop < CONNECTED_DS2482_HUBS; loop++)
+ while(!i8DS2482_OWCheckDeviceReady(&sDS2482[loop]));
+
+ // Get temperature values and display them
+ for(uint8_t z=0; z<u8SensorCount; z++)
+ {
+ int16_t i16Tmp = i16DS2482_OWReadDS1820(sDS1820[z].hub, sDS1820[z].u8RomNr, 0);
+ if(i16Tmp < 0)
+ {
+ console.printf("Error %i\n", -i16Tmp);
+ while(1); // error
+ }
+ else
+ {
+ uint8_t u8Tmp = (i16Tmp-109)/2;
+ uint8_t u8Tmp2;
+ if((int16_t)u8Tmp*2+109 != i16Tmp)
+ u8Tmp2=5;
+ else
+ u8Tmp2=0;
+ console.printf("[%02i] %02i", z+1, u8Tmp);
+ console.printf(",%iC | ", u8Tmp2);
+ }
+ if((z+1)%8==0)
+ console.printf("\n");
+ }
+ }
+}
+*/
+
+/* HW Setup */
+#define DS2482_ADDR1 0x30
+#define DS2482_ADDR2 0x32
+
+#define POLL_LIMIT 50
+
+#define ACK 1
+#define NAK 0
+
+/* DS2482 Status Register Bit Definitions */
+#define STATUS_1WB (1<<0)
+#define STATUS_PPD (1<<1)
+#define STATUS_SD (1<<2)
+#define STATUS_LL (1<<3)
+#define STATUS_RST (1<<4)
+#define STATUS_SBR (1<<5)
+#define STATUS_TSB (1<<6)
+#define STATUS_DIR (1<<7)
+
+/* DS2482 Config Register Definitions */
+#define APU 0x1 // active pullup
+#define SPU 0x4 // strong pullup
+#define OWS 0x8 // 1wire speed
+
+/* Flag Definition */
+#define FLAG_SHORT 0x00000001
+
+/* Error Codes */
+#define DS2482_ERR_NOPRESENCE 2
+#define DS2482_ERR_TIMEOUT 3
+#define DS2482_ERR_I2CWRITE 4
+#define DS2482_ERR_I2CREAD 5
+#define DS2482_ERR_CONFIGMISSMATCH 6
+#define DS2482_ERR_CHECKSUM 7
+
+/* DS2482 Commands */
+#define DRST 0xF0
+#define SRP 0xE1
+#define WCFG 0xD2
+#define OWRS 0xB4
+#define OWSB 0x87
+#define OWWB 0xA5
+#define OWRB 0x96
+#define OWT 0x78
+
+/* 1Wire CRC Definitions */
+#define CRC8INIT 0x00
+#define CRC8POLY 0x18
+