3 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
5 * See file CREDITS for list of people who contributed to this
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25 * Dallas Semiconductor's DS1621/1631 Digital Thermometer and Thermostat.
35 #define DTT_I2C_DEV_CODE 0x48 /* Dallas Semi's DS1621 */
36 #define DTT_READ_TEMP 0xAA
37 #define DTT_READ_COUNTER 0xA8
38 #define DTT_READ_SLOPE 0xA9
39 #define DTT_WRITE_START_CONV 0xEE
40 #define DTT_WRITE_STOP_CONV 0x22
41 #define DTT_TEMP_HIGH 0xA1
42 #define DTT_TEMP_LOW 0xA2
43 #define DTT_CONFIG 0xAC
46 * Config register bits
48 #define DTT_CONFIG_1SHOT 0x01
49 #define DTT_CONFIG_POLARITY 0x02
50 #define DTT_CONFIG_R0 0x04 /* ds1631 only */
51 #define DTT_CONFIG_R1 0x08 /* ds1631 only */
52 #define DTT_CONFIG_NVB 0x10
53 #define DTT_CONFIG_TLF 0x20
54 #define DTT_CONFIG_THF 0x40
55 #define DTT_CONFIG_DONE 0x80
58 int dtt_read(int sensor
, int reg
)
63 /* Calculate sensor address and command */
64 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07); /* Calculate addr of ds1621*/
66 /* Prepare to handle 2 byte result */
77 /* Now try to read the register */
78 if (i2c_read(sensor
, reg
, 1, data
, dlen
) != 0)
81 /* Handle 2 byte result */
83 return (short)((data
[0] << 8) | data
[1]);
89 int dtt_write(int sensor
, int reg
, int val
)
94 /* Calculate sensor address and register */
95 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07);
97 /* Handle various data sizes. */
103 data
[0] = (char)((val
>> 8) & 0xff); /* MSB first */
104 data
[1] = (char)(val
& 0xff);
106 case DTT_WRITE_START_CONV
:
107 case DTT_WRITE_STOP_CONV
:
114 data
[0] = (char)(val
& 0xff);
117 /* Write value to device */
118 if (i2c_write(sensor
, reg
, 1, data
, dlen
) != 0)
121 /* Poll NV memory busy bit in case write was to register stored in EEPROM */
122 while(i2c_reg_read(sensor
, DTT_CONFIG
) & DTT_CONFIG_NVB
)
129 static int _dtt_init(int sensor
)
133 /* Setup High Temp */
134 val
= ((CONFIG_SYS_DTT_MAX_TEMP
* 2) << 7) & 0xff80;
135 if (dtt_write(sensor
, DTT_TEMP_HIGH
, val
) != 0)
138 /* Setup Low Temp - hysteresis */
139 val
= (((CONFIG_SYS_DTT_MAX_TEMP
- CONFIG_SYS_DTT_HYSTERESIS
) * 2) << 7) & 0xff80;
140 if (dtt_write(sensor
, DTT_TEMP_LOW
, val
) != 0)
144 * Setup configuraton register
146 * Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES
148 * We run in polled mode, since there isn't any way to know if this
149 * lousy device is ready to provide temperature readings on power up.
152 if (dtt_write(sensor
, DTT_CONFIG
, val
) != 0)
162 unsigned char sensors
[] = CONFIG_DTT_SENSORS
;
164 for (i
= 0; i
< sizeof(sensors
); i
++) {
165 if (_dtt_init(sensors
[i
]) != 0)
166 printf("DTT%d: FAILED\n", i
+ 1);
168 printf("DTT%d: %i C\n", i
+ 1, dtt_get_temp(sensors
[i
]));
175 int dtt_get_temp(int sensor
)
179 /* Start a conversion, may take up to 1 second. */
180 dtt_write(sensor
, DTT_WRITE_START_CONV
, 0);
181 for (i
= 0; i
<= 10; i
++) {
183 if (dtt_read(sensor
, DTT_CONFIG
) & DTT_CONFIG_DONE
)
187 return (dtt_read(sensor
, DTT_READ_TEMP
) / 256);