Microchip Technology MCP3425EV Data Sheet
MCP3425
DS22072B-page 20
© 2009 Microchip Technology Inc.
5.6.5
ACKNOWLEDGE AND NON-
ACKNOWLEDGE
ACKNOWLEDGE
The Master (microcontroller) and the slave (MCP3425)
use an acknowledge pulse as a hand shake of
communication for each byte. The ninth clock pulse of
each byte is used for the acknowledgement. The clock
pulse is always provided by the Master
(microcontroller) and the acknowledgement is issued
by the receiving device of the byte (Note: The
transmitting device must release the SDA line during
the acknowledge pulse.). The acknowledgement is
achieved by pulling-down the SDA line “LOW” during
the 9th clock pulse by the receiving device.
use an acknowledge pulse as a hand shake of
communication for each byte. The ninth clock pulse of
each byte is used for the acknowledgement. The clock
pulse is always provided by the Master
(microcontroller) and the acknowledgement is issued
by the receiving device of the byte (Note: The
transmitting device must release the SDA line during
the acknowledge pulse.). The acknowledgement is
achieved by pulling-down the SDA line “LOW” during
the 9th clock pulse by the receiving device.
During reads, the Master (microcontroller) can
terminate the current read operation by not providing
an acknowledge bit (not Acknowledge (NAK)) on the
last byte. In this case, the MCP3425 device releases
the SDA line to allow the Master (microcontroller) to
generate a STOP or repeated START condition.
terminate the current read operation by not providing
an acknowledge bit (not Acknowledge (NAK)) on the
last byte. In this case, the MCP3425 device releases
the SDA line to allow the Master (microcontroller) to
generate a STOP or repeated START condition.
The non-acknowledgement (NAK) is issued by
providing the SDA line to “HIGH” during the 9th clock
pulse.
providing the SDA line to “HIGH” during the 9th clock
pulse.
FIGURE 5-5:
Data Transfer Sequence on I
2
C Serial Bus.
SCL
SDA
(A)
(B)
(D)
(D)
(A)
(C)
START
CONDITION
ADDRESS OR
ACKNOWLEDGE
VALID
DATA
ALLOWED
TO CHANGE
STOP
CONDITION