Datasheet

TCN75A
DS21935D-page 20  2010 Microchip Technology Inc.
5.3.3 TEMPERATURE HYSTERESIS
REGISTER (T
HYST
)
The TCN75A has a 16-bit read/write Temperature
Hysteresis register that contains a 9-bit data in two’s
compliment format. This register is used to set a
hysteresis for the T
SET
limit. Therefore, the data
represents a minimum temperature limit. If the ambient
temperature drifts below the specified limit, the
TCN75A asserts an alert output (refer to
Section 5.3.4.3 “ALERT Output Configuration”).
This register uses the nine Most Significant bits (MSbs)
and all other bits are “don’t cares”.
The power-up default value of T
HYST
register is 75°C,
or <0100 1011 0>b in binary.
REGISTER 5-4: TEMPERATURE HYSTERESIS REGISTER (T
HYST
) — ADDRESS <0000 0010>b
Upper Half:
R/W-0 R/W-1 R/W-0 R/W-0 R/W-1 R/W-0 R/W-1 R/W-1
Sign 2
6
°C 2
5
°C 2
4
°C 2
3
°C 2
2
°C 2
1
°C 2
0
°C
bit 15 bit 8
Lower Half:
R/W-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
2
-1
°C 0 0 0 0 0 0 0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown