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Dependencies: C12832 EthernetInterface LM75B mbed-rtos mbed
Fork of app-board-LM75B by
main.cpp@1:6484448034e3, 2012-10-18 (annotated)
- Committer:
- chris
- Date:
- Thu Oct 18 13:09:21 2012 +0000
- Revision:
- 1:6484448034e3
- Parent:
- 0:ce7a8546502b
- Child:
- 2:9e757151de9b
First commit
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
okano | 0:ce7a8546502b | 1 | /* |
okano | 0:ce7a8546502b | 2 | * NXP LM75B temperature sensor test |
okano | 0:ce7a8546502b | 3 | * www.nxp.com/pip/LM75B_2.html |
okano | 0:ce7a8546502b | 4 | * |
okano | 0:ce7a8546502b | 5 | * Expecting to use the pins 9 and 10 for I2C bus |
okano | 0:ce7a8546502b | 6 | * these pins should be pulled-up properly. |
okano | 0:ce7a8546502b | 7 | * |
okano | 0:ce7a8546502b | 8 | * The temperature read out will be shown on terminal on the PC screen. |
okano | 0:ce7a8546502b | 9 | * |
okano | 0:ce7a8546502b | 10 | * In this demo code, two LM75B devices can be driven. |
okano | 0:ce7a8546502b | 11 | * These two devices should have different I2C address setting |
okano | 0:ce7a8546502b | 12 | * using its address pins (LM75B's A0 to A2 (pins 5 to 7)). |
okano | 0:ce7a8546502b | 13 | * One LM75B should have all those pins tied to GND. |
okano | 0:ce7a8546502b | 14 | * And another should have the pin A0(pin7) pulled-up. |
okano | 0:ce7a8546502b | 15 | * |
okano | 0:ce7a8546502b | 16 | * From the software, those devices can be accessed by I2C addresses |
okano | 0:ce7a8546502b | 17 | * "0x90" and "0x92". |
okano | 0:ce7a8546502b | 18 | * It will not be as "0x90" and "0x91" because the address has |
okano | 0:ce7a8546502b | 19 | * 7 bit only and stuffed to left. So the "A0" setting become 0xX2. |
okano | 0:ce7a8546502b | 20 | * The LSB does not care because it will be set by I2C libraly when |
okano | 0:ce7a8546502b | 21 | * it transfer the data for read and write. |
okano | 0:ce7a8546502b | 22 | */ |
okano | 0:ce7a8546502b | 23 | |
okano | 0:ce7a8546502b | 24 | #include "mbed.h" |
okano | 0:ce7a8546502b | 25 | |
okano | 0:ce7a8546502b | 26 | // LM75B IIC address |
okano | 0:ce7a8546502b | 27 | #define LM75B_ADDR 0x90 |
okano | 0:ce7a8546502b | 28 | |
okano | 0:ce7a8546502b | 29 | // LM75B registers |
okano | 0:ce7a8546502b | 30 | #define Conf 0x01 |
okano | 0:ce7a8546502b | 31 | #define Temp 0x00 |
okano | 0:ce7a8546502b | 32 | #define Tos 0x03 |
okano | 0:ce7a8546502b | 33 | #define Thyst 0x02 |
okano | 0:ce7a8546502b | 34 | |
okano | 0:ce7a8546502b | 35 | |
okano | 0:ce7a8546502b | 36 | DigitalOut led[] = { LED4, LED3, LED2, LED1 }; |
okano | 0:ce7a8546502b | 37 | Serial pc(USBTX, USBRX); // tx, rx |
okano | 0:ce7a8546502b | 38 | |
chris | 1:6484448034e3 | 39 | I2C i2c( p28, p27 ); // sda, scl |
okano | 0:ce7a8546502b | 40 | |
okano | 0:ce7a8546502b | 41 | |
okano | 0:ce7a8546502b | 42 | void iic_write( char addr, char reg, char data ); |
okano | 0:ce7a8546502b | 43 | char iic_read( char addr, char reg ); |
okano | 0:ce7a8546502b | 44 | short iic_read_short( char addr, char reg ); |
okano | 0:ce7a8546502b | 45 | void iic_error( void ); |
okano | 0:ce7a8546502b | 46 | |
okano | 0:ce7a8546502b | 47 | void init_temp_sensor( char dev_num ); |
okano | 0:ce7a8546502b | 48 | float get_temp( char dev_num ); |
okano | 0:ce7a8546502b | 49 | |
okano | 0:ce7a8546502b | 50 | int main() { |
okano | 0:ce7a8546502b | 51 | int i; |
okano | 0:ce7a8546502b | 52 | |
okano | 0:ce7a8546502b | 53 | init_temp_sensor( 0 ); |
okano | 0:ce7a8546502b | 54 | |
okano | 0:ce7a8546502b | 55 | while(1) { |
chris | 1:6484448034e3 | 56 | pc.printf( " (%d) temp[0]=%6.3f, \n", i++, get_temp( 0 ) ); |
okano | 0:ce7a8546502b | 57 | wait( 1 ); |
okano | 0:ce7a8546502b | 58 | } |
okano | 0:ce7a8546502b | 59 | } |
okano | 0:ce7a8546502b | 60 | |
okano | 0:ce7a8546502b | 61 | void init_temp_sensor( char dev_num ) |
okano | 0:ce7a8546502b | 62 | { |
chris | 1:6484448034e3 | 63 | dev_num <<= 1; |
okano | 0:ce7a8546502b | 64 | iic_write( LM75B_ADDR | dev_num, Conf, 0x00 ); // configuration |
okano | 0:ce7a8546502b | 65 | pc.printf( "sensor[%d] : Conf register read out = 0x%02X\n", dev_num, iic_read( LM75B_ADDR | dev_num, Conf ) ); |
okano | 0:ce7a8546502b | 66 | pc.printf( "sensor[%d] : Tos register read out = 0x%04X\n", dev_num, iic_read_short( LM75B_ADDR | dev_num, Tos ) ); |
okano | 0:ce7a8546502b | 67 | pc.printf( "sensor[%d] : Thyst register read out = 0x%04X\n", dev_num, iic_read_short( LM75B_ADDR | dev_num, Thyst ) ); |
okano | 0:ce7a8546502b | 68 | } |
okano | 0:ce7a8546502b | 69 | |
okano | 0:ce7a8546502b | 70 | |
okano | 0:ce7a8546502b | 71 | float get_temp( char dev_num ) |
okano | 0:ce7a8546502b | 72 | { |
okano | 0:ce7a8546502b | 73 | dev_num <<= 1; |
okano | 0:ce7a8546502b | 74 | |
okano | 0:ce7a8546502b | 75 | return ( (float)(iic_read_short( LM75B_ADDR | dev_num, Temp )) / 256.0 ); |
okano | 0:ce7a8546502b | 76 | } |
okano | 0:ce7a8546502b | 77 | |
okano | 0:ce7a8546502b | 78 | void iic_write( char addr, char reg, char data ) |
okano | 0:ce7a8546502b | 79 | { |
okano | 0:ce7a8546502b | 80 | char cmd[2]; |
okano | 0:ce7a8546502b | 81 | |
okano | 0:ce7a8546502b | 82 | cmd[ 0 ] = reg; |
okano | 0:ce7a8546502b | 83 | cmd[ 1 ] = data; |
okano | 0:ce7a8546502b | 84 | |
okano | 0:ce7a8546502b | 85 | if ( i2c.write( addr, cmd, 2) ) |
okano | 0:ce7a8546502b | 86 | iic_error(); |
okano | 0:ce7a8546502b | 87 | } |
okano | 0:ce7a8546502b | 88 | |
okano | 0:ce7a8546502b | 89 | char iic_read( char addr, char reg ) |
okano | 0:ce7a8546502b | 90 | { |
okano | 0:ce7a8546502b | 91 | char cmd; |
okano | 0:ce7a8546502b | 92 | int nack; |
okano | 0:ce7a8546502b | 93 | |
okano | 0:ce7a8546502b | 94 | cmd = reg; |
okano | 0:ce7a8546502b | 95 | |
okano | 0:ce7a8546502b | 96 | nack = i2c.write( addr, &cmd, 1); // Send command string |
okano | 0:ce7a8546502b | 97 | nack |= i2c.read( addr, &cmd, 1); // Send command string |
okano | 0:ce7a8546502b | 98 | |
okano | 0:ce7a8546502b | 99 | if ( nack ) |
okano | 0:ce7a8546502b | 100 | iic_error(); |
okano | 0:ce7a8546502b | 101 | |
okano | 0:ce7a8546502b | 102 | return ( cmd ); |
okano | 0:ce7a8546502b | 103 | } |
okano | 0:ce7a8546502b | 104 | |
okano | 0:ce7a8546502b | 105 | |
okano | 0:ce7a8546502b | 106 | short iic_read_short( char addr, char reg ) |
okano | 0:ce7a8546502b | 107 | { |
okano | 0:ce7a8546502b | 108 | char cmd[ 2 ]; |
okano | 0:ce7a8546502b | 109 | int nack; |
okano | 0:ce7a8546502b | 110 | |
okano | 0:ce7a8546502b | 111 | cmd[ 0 ] = reg; |
okano | 0:ce7a8546502b | 112 | |
okano | 0:ce7a8546502b | 113 | nack = i2c.write( addr, cmd, 1); // Send command string |
okano | 0:ce7a8546502b | 114 | nack |= i2c.read( addr, cmd, 2); // Send command string |
okano | 0:ce7a8546502b | 115 | |
okano | 0:ce7a8546502b | 116 | if ( nack ) |
okano | 0:ce7a8546502b | 117 | iic_error(); |
okano | 0:ce7a8546502b | 118 | |
okano | 0:ce7a8546502b | 119 | return ( ((short)cmd[ 0 ]) << 8 | cmd[ 1 ] ); |
okano | 0:ce7a8546502b | 120 | } |
okano | 0:ce7a8546502b | 121 | |
okano | 0:ce7a8546502b | 122 | |
okano | 0:ce7a8546502b | 123 | void iic_error( void ) |
okano | 0:ce7a8546502b | 124 | { |
okano | 0:ce7a8546502b | 125 | pc.printf( "I2C error\n" ); |
okano | 0:ce7a8546502b | 126 | |
okano | 0:ce7a8546502b | 127 | for ( int i = 0; i < 4; i++ ) |
okano | 0:ce7a8546502b | 128 | led[ i ] = i & 0x01; |
okano | 0:ce7a8546502b | 129 | |
okano | 0:ce7a8546502b | 130 | wait ( 0.2 ); |
okano | 0:ce7a8546502b | 131 | |
okano | 0:ce7a8546502b | 132 | for ( int i = 0; i < 4; i++ ) |
okano | 0:ce7a8546502b | 133 | led[ i ] = !(i & 0x01); |
okano | 0:ce7a8546502b | 134 | |
okano | 0:ce7a8546502b | 135 | wait ( 0.2 ); |
okano | 0:ce7a8546502b | 136 | } |
okano | 0:ce7a8546502b | 137 |