Stand-Alone, 10-Channel, 10-Bit System Monitors

18

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Write-Selected Channel Configuration

Registers (Command Code 1100)

The Write-Selected Channel Configuration Register com-

mand, 1100, writes to the three channel configuration

registers for the addressed channel (see Table 3). The

first register to be written is the upper threshold (2 bytes),

followed by the lower threshold (2 bytes), ending with the

channel configuration register (1 byte), all MSB first.

Writing to the configuration registers resets the alarm reg-

ister bits and the fault counters for the addressed chan-

nel. See the

Channel Registers section for more details.

Write Global Configuration Registers

(Command Code 1101)

The Write Global Configuration Registers command,

1101, writes to three registers: the channel-enable reg-

ister (2 bytes), the input configuration register (2 bytes),

and the setup register (1 byte). The command address

bits are ignored. See the

Global Configuration

Registers section for more details.

Global Configuration Registers

The global configuration registers consist of the chan-

nel-enable register, the input configuration register, and

the setup register. These registers hold configuration

data common to all channels.

Channel-Enable Register

The channel-enable register (Table 4) controls which

channels are converted while in automatic scan mode.

The register contents are ignored for manual conver-

sion commands. Each input channel has a correspond-

ing bit in the channel-enable register. A logic high

enables the corresponding analog input channel for

conversion, while a logic low disables it. In differential

configuration, the bits for odd channels are ignored. At

power-up and after a RESET command, the register

contents default to 111111111111b (all channels

enabled).

Input Configuration Register

The input configuration register (Table 5) stores the

configuration code for each channel as a 3-bit per

channel-pair code (see Table 6), selecting from five

input signal configurations: single-ended unipolar volt-

age, single-ended temperature, differential unipolar

voltage, differential bipolar voltage, and differential

temperature. Table 5 shows the input configuration reg-

ister format, and Table 6 shows the 3-bit encoding for

channel configuration. At power-up and after a RESET

command, the register contents defaults to

000000000000b (all inputs single ended).

Table 4. Channel-Enable Register Format

B11

(MSB)

B10

B9B8B7B6B5B4B3B2B1

B0

(LSB)

TEMP

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

Res

Res

Table 5. Input Configuration Register Format

B11

(MSB)

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

(LSB)

AIN0 and AIN1 configuration

AIN2 and AIN3 configuration

AIN4 and AIN5 configuration

AIN6 and AIN7 configuration

Table 6. Channel Configuration Coding (3 Bits/Channel Pair)

CODE

AIN0, AIN2, AIN4, AIN6 CONFIGURATION

AIN1, AIN3, AIN5, AIN7 CONFIGURATION

000

Single-ended input (power-up state)

Single-ended input (power-up state)

001

Single-ended input

Single-ended, external temperature sensor input

010

Single-ended, external temperature sensor input

Single-ended input

011

Single-ended, external temperature sensor input

Single-ended, external temperature sensor input

100

Differential unipolar encoded, positive input

Differential unipolar encoded, negative input

101

Differential bipolar encoded, positive input

Differential bipolar encoded, negative input

110

Differential external temperature sensor, positive input

Differential external temperature sensor, negative input

111

Reserved

Reserved