Microchip Technology MCP3421DM-WS Data Sheet
© 2009 Microchip Technology Inc.
DS22003E-page 23
MCP3421
5.6.5
ACKNOWLEDGE AND NON-
ACKNOWLEDGE
ACKNOWLEDGE
The Master (microcontroller) and the slave (MCP3421)
use an acknowledge pulse as a hand shake of commu-
nication 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 commu-
nication 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 MCP3421 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 MCP3421 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 5-6:
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