EZ80F91MCU Datasheet, PDF (248/396 Pages) Zilog, Inc. – eZ80Acclaim-TM Flash Microcontrollers

eZ80F91 MCU
Product Specification
229
If 10-bit addressing is being used, the slave is first addressed using the full 10-bit
address, plus the Write bit. The master then issues a restart followed by the first
part of the 10-bit address again, this time with the Read bit. The status code then
becomes 40h or 48h. It is the responsibility of the slave to remember that it had
been selected prior to the restart.
If a repeated START condition is received, the status code is 10h instead of 08h.
After each data byte is received, the IFLG is set to 1 and one of the status codes
listed in Table 122 is loaded into the I2C_SR register.
Table 122. I²C Master Receive Status Codes For Data Bytes
Code I²C State
Microcontroller Response Next I²C Action
50h
Data byte received, Read data, clear IFLG,
ACK transmitted
clear AAK = 0*
Receive data byte,
transmit NACK
Or read data, clear IFLG,
set AAK = 1
Receive data byte,
transmit ACK
58h
Data byte received, Read data, set STA,
NACK transmitted
clear IFLG
Transmit repeated
START
Or read data, set STP,
clear IFLG
Transmit STOP
Or read data, set
STA & STP, clear IFLG
Transmit STOP
then
START
38h
Arbitration lost in
Same as master transmit
Same as master
NACK bit
transmit
Note: AAK is an I²C control bit that identifies which ACK signal to transmit.
When all bytes are received, a NACK should be sent, then the microcontroller
should write a 1 to the STP bit in the I2C_CTL register. The I²C then transmits a
STOP condition, clears the STP bit and returns to an idle state.
Slave Transmit
In SLAVE TRANSMIT mode, a number of bytes are transmitted to a master
receiver.
The I²C enters SLAVE TRANSMIT mode when it receives its own slave address
and a Read bit after a START condition. The I²C then transmits an ACK bit (if the
AAK bit is set to 1); it then sets the IFLG bit in the I2C_CTL register. As a result,
the I2C_SR register contains the status code A8h.
PS019209-0504
PRELIMINARY
I²C Serial I/O Interface