Datasheet

AMC7812
SBAS513E –JANUARY 2011–REVISED SEPTEMBER 2013 www.ti.com
ANALOG INPUT CHANNEL THRESHOLD REGISTERS (Read/Write, Addresses = 5Ah to 61h)
Four analog auxiliary inputs (CH0, CH1, CH2, and CH3) and three temperature sensors (LT, D1, and D2)
implement an out-of-range alarm function. Threshold-High-n and Threshold-Low-n (where n = 0, 1, 2, 3) define
the upper bound and lower bound of the nth analog input range, as shown in Table 27. This window determines
whether the nth input is out-of-range. When the input is outside the window, the corresponding CH-ALR-n bit in
the Status Register is set to '1'.
For normal operation, the value of Threshold-High-n must be greater than the value of Threshold-Low-n;
otherwise, CH-ALR-n is always set to '1' and an alarm is always indicated. Note that when the analog channel is
accessed as single-ended input, its threshold is in a straight binary format. However, when the channel is
accessed as a differential pair, its threshold is in twos complement format.
Table 27. Threshold Coding
INPUT CHANNEL INPUT TYPE THRESHOLD STORED IN FORMAT
Input-0-Threshold-High-Byte
Channel 0 Single-Ended Straight binary
Input-0-Threshold-Low-Byte
Input-1-Threshold- High-Byte
Channel 1 Single-Ended Straight binary
Input-1-Threshold- Low-Byte
Input-2-Threshold- High-Byte
Channel 2 Single-Ended Straight binary
Input-2-Threshold- Low-Byte
Input-3-Threshold- High-Byte
Channel 3 Single-Ended Straight binary
Input-3-Threshold- Low-Byte
Input-0-Threshold- High-Byte
CH0+/CH1– Differential Twos complement
Input-0-Threshold- Low-Byte
Input-2-Threshold- High-Byte
CH2+/CH3– Differential Twos complement
Input-2-Threshold- Low-Byte
Input-n-High-Threshold Register (where n = 0, 1, 2, 3) (Read/Write, Default = 0FFFh)
MSB LSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
THRH THRH THRH THRH THRH THRH THRH THRH THRH THRH THRH THRH
0 0 0 0
11 10 9 8 7 6 5 4 3 2 1 0
Bits[15:12] Reserved. These bits are '0' when read back. Writing to these bits has no effect.
Bits[11:0] THRHn: Data bits of the upper-bound threshold of the nth analog input.
Input-n-Low-Threshold Register (where n = 0, 1, 2, 3) (Read/Write, Default = 0000h)
MSB LSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
THRL THRL THRL THRL THRL THRL THRL THRL THRL THRL THRL THRL
0 0 0 0
11 10 9 8 7 6 5 4 3 2 1 0
Bits[15:12] Reserved. These bits are '0' when read back. Writing to these bits has no effect.
Bits[11:0] THRLn: Data bits of the lower-bound threshold of the nth analog input.
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