Datasheet

MCP4728
DS22187E-page 24 © 2010 Microchip Technology Inc.
4.4 DAC Input Registers and
Non-Volatile EEPROM Memory
Each channel has its own volatile DAC input register
and EEPROM. The details of the input registers and
EEPROM are shown in Table 4-1 and Table 4-2,
respectively.
TABLE 4-1: INPUT REGISTER MAP (VOLATILE)
Configuration Bits DAC Input Data (12 bits)
Bit
Name
RDY
/BSY
A2 A1 A0 VREF DAC1 DAC0 PD1 PD0 GX D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Bit
Function
(Note 1)
I
2
C
Address Bits
(Note 2)
Ref.
Select
(Note 2)
DAC Channel
(Note 2)
Power-Down
Select
(Note 2)
Gain
Select
(Note 2)
(Note 2)
CH. A
CH. B
CH. C
CH. D
Note 1: EEPROM write status indication bit (flag).
2: Loaded from EEPROM during power-up, or can be updated by the user.
TABLE 4-2: EEPROM MEMORY MAP AND FACTORY DEFAULT SETTINGS
Configuration Bits DAC Input Data (12 bits)
Bit Name
A2 A1 A0 VREF PD1 PD0 GX D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Bit
Function I
2
C Address Bits
(Note 1)
Ref.
Select
(Note 2)
Power-Down
Select
Gain
Select
(Note 3)
CH. A 0 0 0 1 0 0 0 0 0 0 000000000
CH. B 1 0 0 0 0 0 0 000000000
CH. C 1 0 0 0 0 0 0 000000000
CH. D 1 0 0 0 0 0 0 000000000
Note 1: Device I
2
C address bits. The user can also specify these bits during the device ordering process. The
factory default setting is “000”. These bits can be reprogrammed by the user using the I
2
C Address Write
command.
2: Voltage Reference Select: 0 = External V
REF
(V
DD
), 1 = Internal V
REF
(2.048V).
3: Gain Select: 0 = Gain of 1, 1 = Gain of 2.