CUER
CUER version of the DS1820 library
Diff: DS1820.cpp
- Revision:
- 1:91aa74f0cb0e
- Parent:
- 0:245af9360f0d
- Child:
- 2:4c7277e9f267
--- a/DS1820.cpp Tue Feb 28 07:42:07 2012 +0000
+++ b/DS1820.cpp Sun Jul 02 15:10:13 2017 +0000
@@ -1,15 +1,16 @@
#include "DS1820.h"
#include "mbed.h"
-
+
// Global variables shared between all DS1820 objects
bool DS1820_done_flag;
int DS1820_last_descrepancy;
char DS1820_search_ROM[8];
-
-
+
+
DS1820::DS1820 (PinName data_pin, PinName power_pin) : _datapin(data_pin), _parasitepin(power_pin) {
int byte_counter;
_parasite_power = true;
+ _parasitepin = 1; //Initial value set high, P-channel mosfet is off so data can transmit
for(byte_counter=0;byte_counter<8;byte_counter++)
ROM[byte_counter] = 0xFF;
for(byte_counter=0;byte_counter<9;byte_counter++)
@@ -23,7 +24,7 @@
for(byte_counter=0;byte_counter<9;byte_counter++)
RAM[byte_counter] = 0x00;
}
-
+
bool DS1820::onewire_reset() {
// This will return false if no devices are present on the data bus
bool presence=false;
@@ -37,7 +38,7 @@
wait_us(410);
return presence;
}
-
+
void DS1820::onewire_bit_out (bool bit_data) {
_datapin.output();
_datapin = 0;
@@ -50,7 +51,7 @@
_datapin.input();
}
}
-
+
void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
int n;
for (n=0; n<8; n++) {
@@ -58,7 +59,7 @@
data = data >> 1; // now the next bit is in the least sig bit position.
}
}
-
+
bool DS1820::onewire_bit_in() {
bool answer;
_datapin.output();
@@ -70,7 +71,7 @@
wait_us(50);
return answer;
}
-
+
char DS1820::onewire_byte_in() { // read byte, least sig byte first
char answer = 0x00;
int i;
@@ -81,15 +82,15 @@
}
return answer;
}
-
+
bool DS1820::search_ROM() {
return search_ROM_routine(0xF0); // Search ROM command
}
-
+
bool DS1820::search_alarm() {
return search_ROM_routine(0xEC); // Search Alarm command
}
-
+
bool DS1820::search_ROM_routine(char command) {
extern bool DS1820_done_flag;
extern int DS1820_last_descrepancy;
@@ -97,7 +98,7 @@
int descrepancy_marker, ROM_bit_index;
bool return_value, Bit_A, Bit_B;
char byte_counter, bit_mask;
-
+
return_value=false;
if (!DS1820_done_flag) {
if (!onewire_reset()) {
@@ -158,7 +159,7 @@
}
return return_value;
}
-
+
void DS1820::search_ROM_setup() {
extern bool DS1820_done_flag;
extern int DS1820_last_descrepancy;
@@ -169,7 +170,7 @@
for (i=0; i<8; i++)
DS1820_search_ROM[i]=0x00;
}
-
+
void DS1820::read_ROM() {
// NOTE: This command can only be used when there is one DS1820 on the bus. If this command
// is used when there is more than one slave present on the bus, a data collision will occur
@@ -180,7 +181,7 @@
for (i=0; i<8; i++)
ROM[i]=onewire_byte_in();
}
-
+
void DS1820::match_ROM() {
// Used to select a specific device
int i;
@@ -189,77 +190,89 @@
for (i=0;i<8;i++)
onewire_byte_out(ROM[i]);
}
-
+
void DS1820::skip_ROM() {
onewire_reset();
onewire_byte_out(0xCC); // Skip ROM command
}
-
+
bool DS1820::ROM_checksum_error() {
- char CRC=0x00;
+ char crc=0x00;
int i;
for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
- CRC = CRC_byte(CRC, ROM[i]);
- // After 7 bytes CRC should equal the 8th byte (ROM CRC)
- return (CRC!=ROM[7]); // will return true if there is a CRC checksum error
+ crc = CRC_byte(crc, ROM[i]);
+ // After 7 bytes crc should equal the 8th byte (ROM crc)
+ return (crc!=ROM[7]); // will return true if there is a crc checksum error
}
-
+
bool DS1820::RAM_checksum_error() {
- char CRC=0x00;
+ char crc=0x00;
int i;
read_RAM();
for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
- CRC = CRC_byte(CRC, RAM[i]);
- // After 8 bytes CRC should equal the 9th byte (RAM CRC)
- return (CRC!=RAM[8]); // will return true if there is a CRC checksum error
+ crc = CRC_byte(crc, RAM[i]);
+ // After 8 bytes crc should equal the 9th byte (RAM crc)
+ return (crc!=RAM[8]); // will return true if there is a crc checksum error
}
-
-char DS1820::CRC_byte (char CRC, char byte ) {
+
+char DS1820::CRC_byte (char crc, char byte ) {
int j;
for(j=0;j<8;j++) {
- if ((byte & 0x01 ) ^ (CRC & 0x01)) {
- // DATA ^ LSB CRC = 1
- CRC = CRC>>1;
+ if ((byte & 0x01 ) ^ (crc & 0x01)) {
+ // DATA ^ LSB crc = 1
+ crc = crc>>1;
// Set the MSB to 1
- CRC = CRC | 0x80;
+ crc = crc | 0x80;
// Check bit 3
- if (CRC & 0x04) {
- CRC = CRC & 0xFB; // Bit 3 is set, so clear it
+ if (crc & 0x04) {
+ crc = crc & 0xFB; // Bit 3 is set, so clear it
} else {
- CRC = CRC | 0x04; // Bit 3 is clear, so set it
+ crc = crc | 0x04; // Bit 3 is clear, so set it
}
// Check bit 4
- if (CRC & 0x08) {
- CRC = CRC & 0xF7; // Bit 4 is set, so clear it
+ if (crc & 0x08) {
+ crc = crc & 0xF7; // Bit 4 is set, so clear it
} else {
- CRC = CRC | 0x08; // Bit 4 is clear, so set it
+ crc = crc | 0x08; // Bit 4 is clear, so set it
}
} else {
- // DATA ^ LSB CRC = 0
- CRC = CRC>>1;
+ // DATA ^ LSB crc = 0
+ crc = crc>>1;
// clear MSB
- CRC = CRC & 0x7F;
- // No need to check bits, with DATA ^ LSB CRC = 0, they will remain unchanged
+ crc = crc & 0x7F;
+ // No need to check bits, with DATA ^ LSB crc = 0, they will remain unchanged
}
byte = byte>>1;
}
-return CRC;
+return crc;
}
-
+
void DS1820::convert_temperature(devices device) {
// Convert temperature into scratchpad RAM for all devices at once
+ int delay_time = 750; // Default delay time
+ char resolution;
if (device==all_devices)
skip_ROM(); // Skip ROM command, will convert for ALL devices
- else
+ else {
match_ROM();
+ if (FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
+ resolution = RAM[4] & 0x60;
+ if (resolution == 0x00) // 9 bits
+ delay_time = 94;
+ if (resolution == 0x20) // 10 bits
+ delay_time = 188;
+ if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
+ delay_time = 375;
+ }
+ }
onewire_byte_out( 0x44); // perform temperature conversion
if (_parasite_power)
- _parasitepin = 1; // Parasite power strong pullup
- wait_ms(750);
+ _parasitepin = 0; // Parasite power strong pullup
+ wait_ms(delay_time);
if (_parasite_power)
- _parasitepin = 0;
+ _parasitepin = 1;
}
-
+
void DS1820::read_RAM() {
// This will copy the DS1820's 9 bytes of RAM data
// into the objects RAM array. Functions that use
@@ -271,14 +284,27 @@
RAM[i] = onewire_byte_in();
}
}
-
+
+bool DS1820::set_configuration_bits(unsigned int resolution) {
+ bool answer = false;
+ resolution = resolution - 9;
+ if (resolution < 4) {
+ resolution = resolution<<5; // align the bits
+ RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
+ write_scratchpad ((RAM[2]<<8) + RAM[3]);
+// store_scratchpad (DS1820::this_device); // Need to test if this is required
+ answer = true;
+ }
+ return answer;
+}
+
int DS1820::read_scratchpad() {
int answer;
read_RAM();
answer = (RAM[2]<<8) + RAM[3];
return answer;
}
-
+
void DS1820::write_scratchpad(int data) {
RAM[3] = data;
RAM[2] = data>>8;
@@ -286,8 +312,11 @@
onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
onewire_byte_out(RAM[2]); // T(H)
onewire_byte_out(RAM[3]); // T(L)
+ if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
+ onewire_byte_out(RAM[4]); // Configuration register
+ }
}
-
+
void DS1820::store_scratchpad(devices device) {
if (device==all_devices)
skip_ROM(); // Skip ROM command, will store for ALL devices
@@ -295,12 +324,12 @@
match_ROM();
onewire_byte_out(0x48); // Write scratchpad into E2 command
if (_parasite_power)
- _parasitepin=1;
+ _parasitepin=0;
wait_ms(10); // Parasite power strong pullup for 10ms
if (_parasite_power)
- _parasitepin=0;
+ _parasitepin=1;
}
-
+
int DS1820::recall_scratchpad(devices device) {
// This copies the E2 values into the DS1820's memory.
// If you specify all_devices this will return zero, otherwise
@@ -319,7 +348,7 @@
}
return answer;
}
-
+
float DS1820::temperature(char scale) {
// The data specs state that count_per_degree should be 0x10 (16), I found my devices
// to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
@@ -333,10 +362,15 @@
if (reading & 0x8000) { // negative degrees C
reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
}
- remaining_count = RAM[6];
- count_per_degree = RAM[7];
- answer = reading +0.0;
- answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree;
+ answer = reading +0.0; // convert to floating point
+ if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
+ answer = answer / 8.0;
+ }
+ else {
+ remaining_count = RAM[6];
+ count_per_degree = RAM[7];
+ answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree;
+ }
if (scale=='C' or scale=='c')
answer = answer / 2.0;
else
@@ -344,7 +378,7 @@
answer = answer * 9.0 / 10.0 + 32.0;
return answer;
}
-
+
bool DS1820::read_power_supply(devices device) {
// This will return true if the device (or all devices) are Vcc powered
// This will return false if the device (or ANY device) is parasite powered
@@ -355,3 +389,5 @@
onewire_byte_out(0xB4); // Read power supply command
return onewire_bit_in();
}
+
+
\ No newline at end of file