Acknowledge/Negative Acknowledge - Fujitsu MB86R02 Jade-D Hardware Manual

MB86R02 'Jade-D' Hardware Manual V1.64

29.8.6 Acknowledge/Negative acknowledge

The nineth bit of data indicates an acknowledge (ACK)/negative acknowledge (NACK). A status of "0" is
acknowledge and "1" is a negative acknowledge.
The reception side transmits a acknowledge/negative acknowledge to the transmitter and this is stored
in the LRB bit on data reception.
If an acknowledge is not received from the master reception side during slave transmission (when a
negative acknowledge is received), the state becomes TRX = "0" and the mode changes to slave
reception mode. As a result, the master is able to generate a stop condition when the slave opens the
SCL line.
I2C_SDAx
I2C_SCLx
Macro A (transmission)
SDA output
SCL output
Macro B (reception)
SDA output
SCL output
1 2 3 4
Transmission side opens bus for
Master generates
ACK/NACK output on reception
clock
side
Reception side returns
ACK/NACK to transmission side
ACK
5 6 7 8
ACK
9
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