TC74A5 Microchip Technology, TC74A5 Datasheet - Page 9

• Manufacturer Part Number: TC74A5
• Description: Tiny Serial Digital Thermal Sensor
• Manufacturer: Microchip Technology

4.0
TABLE 4-1:
TABLE 4-2:
FIGURE 4-1:
4.1
The binary value (2’s complement format) in this regis-
ter represents temperature of the onboard sensor
following a conversion cycle. The registers are
automatically updated in an alternating manner.
©
*Note: DATA_RDY bit RESET at power-up and SHDN
enable.
DATA_RDY
COMMAND CODE
D[5]-D[0]
2002 Microchip Technology Inc.
BIT
D[7]
D[6]
RWCR
RTR
SHDN
V
DD
REGISTER SET AND
PROGRAMMER’S MODEL
Temperature Register (TEMP),
8 Bits, READ ONLY
POR
0
0
0
00h
01h
zero when read
Always returns
COMMAND BYTE
DESCRIPTION
(SMBUS READ_BYTE AND
WRITE_BYTE)
CONFIGURATION REGISTER
(CONFIG); 8 BITS, READ/
WRITE)
FUNCTION
Data Ready*
Reserved -
STANDBY
Switch
DATA_RDY, SHDN
OPERATION LOGIC
DIAGRAM
Read Temperature (TEMP)
Read/Write Configuration
(CONFIG)
t conv
FUNCTION
TYPE OPERATION
Read/
Write
Read
Only
N/A
0 = not ready
1 = standby,
0 = normal
1 = ready
t conv
N/A
complement binary format such that a reading of 0000
TABLE 4-3:
I
sents one degree (Celsius). The value is in 2’s
0000b corresponds to 0°C. Examples of this tempera-
ture to binary value relationship are shown in Table 4-4
TABLE 4-4:
4.2
The TC74 register set is summarized in Table 4-5. All
registers are 8 bits wide.
TABLE 4-5:
n the temperature data registers, each unit value repre-
*Note: The TEMP resigister will be immediately updated by
the A/D converter after the DATA_RDY Bit goes High.
CONFIG
MSB
D[7]
NAME
TEMP
ACTUAL
+130.00°C
+127.00°C
+126.50°C
+25.25°C
-25.00°C
-25.25°C
-54.75°C
-55.00°C
-65.00°C
+0.50°C
+0.25°C
TEMP.
-0.25°C
-0.50°C
-0.75°C
-1.00°C
0.00°C
D[6]
Register Set Summary
X
DESCRIPTION
Internal Sensor
Complement)
Temp. (2’s
CONFIG
Register
D[5]
X
(TEMP)
VALUE CONVERSION (TEMP)
SUMMARY
TEMPERATURE REGISTER
TEMPERATURE TO DIGITAL
TC74 REGISTER SET
REGISTERED
TEMP.
+127°C
+127°C
+127°C
D[4]
+25°C
-25°C
-25°C
-55°C
-55°C
-65°C
+1°C
-1°C
-1°C
0°C
0°C
0°C
0°C
X
0000 0000b*
0000 0000b
POR State
D[3] D[2] D[1]
X
X
DS21462B-page 9
READ WRITE
0001 1001
0000 0001
0000 0000
0000 0000
0000 0000
0000 0000
1100 1001
1100 1001
1110 0110
0111 1111
0111 1111
0111 1111
1110 0111
1011 1111
BINARY
1111 1111
1111 1111
TC74


HEX
X
D[0]
LSB

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