TC74A0-3.3VCTTRG View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
TC74A0-3.3VCTTRG Datasheet PDF : 18 Pages
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TC74
4.0 REGISTER SET AND
PROGRAMMER’S MODEL
TABLE 4-1:
COMMAND BYTE
DESCRIPTION
(SMBUS/I2C READ_BYTE AND
WRITE_BYTE)
Command Code
Function
RTR
RWCR
00h Read Temperature (TEMP)
01h Read/Write Configuration
(CONFIG)
TABLE 4-2:
CONFIGURATION REGISTER
(CONFIG); 8 BITS, READ/
WRITE)
Bit POR Function Type Operation
D[7] 0 STANDBY Read/ 1 = standby,
Switch
Write 0 = normal
D[6] 0 Data Ready * Read 1 = ready
Only 0 = not ready
D[5]-
D[0]
0 Reserved -
Always
returns zero
when read
N/A N/A
Note 1: *DATA_RDY bit RESET at power-up and
SHDN enable.
VDD
DATA_RDY
SHDN
tconv
tconv
FIGURE 4-1:
DATA_RDY, SHDN
Operation Logic Diagram.
4.1 Temperature Register (TEMP),
8 Bits, READ ONLY
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.
TABLE 4-3: TEMPERATURE REGISTER
(TEMP)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB X
X
X X X X LSB
In temperature data registers, each unit value repre-
sents one degree (Celsius). The value is in 2’s
complement binary format such that a reading of 0000
0000b corresponds to 0°C. Examples of this
temperature to binary value relationship are shown in
Table 4-4.
TABLE 4-4:
Actual
Temperature
+130.00°C
+127.00°C
+126.50°C
+25.25°C
+0.50°C
+0.25°C
0.00°C
-0.25°C
-0.50°C
-0.75°C
-1.00°C
-25.00°C
-25.25°C
-54.75°C
-55.00°C
-65.00°C
TEMPERATURE-TO-DIGITAL
VALUE CONVERSION
(TEMP)
Registered
Temperature
Binary
Hex
+127°C
0111 1111
+127°C
0111 1111
+126°C
0111 1110
+25°C
0001 1001
0°C
0000 0000
0°C
0000 0000
0°C
0000 0000
-1°C
1111 1111
-1°C
1111 1111
-1°C
1111 1111
-1°C
1111 1111
-25°C
1110 0111
-26°C
1110 0110
-55°C
1100 1001
-55°C
1100 1001
-65°C
1011 1111
4.2 Register Set Summary
The TC74 register set is summarized in Table 4-5. All
registers are 8 bits wide.
TABLE 4-5: TC74 REGISTER SET
SUMMARY
Name
Description
POR
State
Read Write
TEMP Internal Sensor 0000
Temperature (2’s 0000b (1) N/A
Complement)
CONFIG
CONFIG
Register
0000
0000b
Note 1: The TEMP register will be immediately
updated by the A/D converter after the
DATA_RDY Bit goes high.
DS21462D-page 8
2001-2012 Microchip Technology Inc.
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