ADM1176-1ARMZ-R7(Rev0) View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

ADM1176-1ARMZ-R7
(Rev.:Rev0)

Hot Swap Controller and I2C® Power Monitor with Convert Pin

Analog Devices 

ADM1176

READ VOLTAGE AND/OR CURRENT DATA BYTES

The ADM1176 can be set up to provide information in three

different ways (see the Write Command Byte section). Depending

on how the device is configured, the following data can be read

out of the device after a conversion (or conversions).

Voltage and Current Readback

The ADM1176 digitizes both voltage and current. Three bytes

are read out of the device in the format shown in Table 12.

Table 12. Voltage and Current Readback Format

Byte Contents B7 B6 B5 B4 B3 B2 B1 B0

1

Voltage V11 V10 V9 V8 V7 V6 V5 V4

MSBs

2

Current I11 I10 I9 I8 I7 I6 I5 I4

MSBs

3

LSBs

V3 V2 V1 V0 I3 I2 I1 I0

Voltage Readback

The ADM1176 digitizes voltage only. Two bytes are read out of

the device in the format shown in Table 13.

Table 13. Voltage Only Readback Format

Byte Contents

B7 B6 B5 B4 B3 B2 B1 B0

1 Voltage MSBs V11 V10 V9 V8 V7 V6 V5 V4

2 Voltage LSBs V3 V2 V1 V0 0 0 0 0

Current Readback

The ADM1176 digitizes current only. Two bytes are read out of

the device in the format shown in Table 14.

Table 14. Current Only Readback Format

Byte Contents

B7 B6 B5 B4 B3 B2 B1 B0

1 Current MSBs I11 I10 I9 I8 I7 I6 I5 I4

2 Current LSBs I3 I2 I1 I0 0 0 0 0

The following series of events occur when the master receives

three bytes (voltage and current data) from the slave device:

1. The master device asserts a start condition on SDA.

2. The master sends the 7-bit slave address, followed by the

read bit (high).

3. The addressed slave device asserts an acknowledge on SDA.

4. The master receives the first data byte.

5. The master asserts an acknowledge on SDA.

6. The master receives the second data byte.

7. The master asserts an acknowledge on SDA.

8. The master receives the third data byte.

9. The master asserts a no acknowledge on SDA.

10. The master asserts a stop condition on SDA, and the

transaction ends.

For cases where the master is reading voltage only or current

only, only two data bytes are read. Step 7 and Step 8 are not

required.

1

2

3 4 5 6 7 8 9 10

S

SLAVE

ADDRESS

R

A

DATA 1

A

DATA 2

A

DATA 3

N

P

Figure 38. Three-Byte Read from ADM1176

1

2

3

4

5

6

78

S

SLAVE

ADDRESS

R

A

REGISTER

ADDRESS

A

REGISTER

DATA

NP

Figure 39. Two-Byte Read from ADM1176

Converting ADC Codes to Voltage and Current Readings

The following equations can be used to convert ADC codes

representing voltage and current from the ADM1175 12-bit

ADC into actual voltage and current values.

Voltage = (VFULLSCALE/4096) × Code

where:

VFULLSCALE = 6.65 (7:2 range) or 26.35 (14:1 range).

Code is the ADC voltage code read from the device (Bit V0

to V11).

Current = ((IFULLSCALE/4096) × Code)/Sense Resistor

where:

IFULLSCALE = 105.84 mV.

Code is the ADC current code read from the device (Bit I0

to Bit I11).

Read Status Register

A single register of status data can also be read from the

ADM1176.

1. The master device asserts a start condition on SDA.

2. The master sends the 7-bit slave address, followed by the

read bit (high).

3. The addressed slave device asserts an acknowledge on SDA.

4. The master receives the status byte.

5. The master asserts an acknowledge on SDA.

1

2

34 5

S

SLAVE

ADDRESS

R

A

DATA 1

A

Figure 40. Status Read from ADM1176

Table 15 shows the ADM1176 status registers in detail. Note

that Bit 1, Bit 3, and Bit 5 are cleared by writing to Bit 4 of the

ALERT_EN register (CLEAR).

Rev. 0 | Page 20 of 24

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