Datasheet

© 2010 Microchip Technology Inc. DS22187E-page 31
MCP4728
5.4 I
2
C General Call Commands
The device acknowledges the general call address
command (0x00 in the first byte). The meaning of the
general call address is always specified in the second
byte. The I
2
C specification does not allow the use of
00000000” (00h) in the second byte. Refer to the
Philips I
2
C document for more details of the General
Call specifications.
The MCP4728 device supports the following I
2
C
General Calls:
General Call Reset
General Call Wake-Up
General Call Software Update
General Call Read Address Bits
5.4.1 GENERAL CALL RESET
The General Call Reset occurs if the second byte is
00000110” (06h). At the acknowledgement of this
byte, the device will abort the current conversion and
perform the following tasks:
Internal Reset similar to a Power-on Reset (POR).
The contents of the EEPROM are loaded into
each DAC input and output registers immediately
• V
OUT
will be available immediately regardless of
the LDAC
pin condition
FIGURE 5-3: General Call Reset.
5.4.2
GENERAL CALL WAKE-UP
If the second byte is “00001001” (09h), the device will
reset the Power-Down bits (PD1, PD0 = 0,0).
FIGURE 5-4: General Call Wake-Up.
1st Byte
Note 1
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
Stop
Start
2nd Byte
ACK (MCP4728)
(General Call Command)
(Command Type = General Call Reset)
Clock Pulse (CLK Line)
Data (SDA Line)
Note 1: At this falling edge of the last ACK clock bit:
a. Startup Timer starts a reset sequence and
b. EEPROM data is loaded into the DAC Input and Output Registers immediately.
1st Byte
Note 1
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
Stop
Start
2nd Byte
ACK (MCP4728)
(General Call Command)
(Command Type = General Call Wake-Up)
Clock Pulse (CLK Line)
Data (SDA Line)
Note 1: Resets Power-Down bits at this falling edge of the last ACK clock bit.