Rainbow Electronics MAX6662 - Manual (Page 7)

MAX6662
12-Bit + Sign Temperature Sensor with
SPI-Compatible Serial Interface
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The first bit of the command byte is always high to sig-
nify a Start, and the second bit is an R/
W bit, high for
read and low for write. There are a total of 11 valid
commands. The temperature conversion runs continu-
ously and asynchronously from the serial interface.
When the Temperature register is read, any conversion
in progress is aborted and the data output is from the
previous conversion. A new conversion is started each
time the serial interface is accessed.
MAX6662 Registers
The MAX6662 has six registers: Temperature, Configura-
tion, T
HYST , T MAX , T LOW , and T HIGH registers. They are
all 16 bits (Figure 5). The Temperature register is read
only; all other registers can be read from or written to.
Temperature Register
The MSB of the Temperature register is the sign bit. The
next 12 bits are temperature data. The digital tempera-
ture data for the most recent temperature conversion is
TEMPERATURE REGISTER (COMMAND = C1H)
Label
15
Sign
Bit
14
Data
MSB
13 12 11 10 9 8 7 6 5 4 3
Data
LSB
2
T OVER
Flag
1
T HIGH
Flag
0
T LOW
Flag
POR
State
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
CONFIGURATION REGISTER (COMMAND = C3H FOR READING; COMMAND = 83H FOR WRITING)
Label
15
*
14
*
13
*
12
Fault
Queue
11
ALERT
Polarity
10
OT
Polarity
9
Interrupt
Mode
8
Shutdown
Mode
7
*
6
*
5
*
4
*
3
*
2
*
1
*
0
*
POR
State
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
TEMPERATURE LIMIT REGISTERS (T HYST , T MAX , T LOW , T HIGH ) (TABLE 2)
Label
15
Sign
14
Data
MSB
13 12 11 10 9 8 7
Data
LSB
6
*
5
*
4
*
3
*
2
*
1
*
0
*
POR
State
**
* Reserved (not used). Writing to this bit is ignored.
** THYST register: 0000 0001 0000 0000b (2°C)
** TMAX register: 0010 1000 0000 0000b (+80°C)
** TLOW register: 0000 0101 0000 0000b (+10°C)
** THIGH register: 0010 0000 0000 0000b (+64°C)
Figure 5. Bit Assignment for the MAX6662 Registers
COMMAND DESCRIPTION
C1h Temperature register read
C3h Configuration register read
C5h T HYST register read
C7h T MAX register read
C9h T LOW register read
CBh T HIGH register read
83h Configuration register write
85h T HYST register write
87h T MAX register write
89h T LOW register write
8Bh T HIGH register write
Table 2. Command Codes for the
Temperature Limit Registers