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Table 16.8. I²C Slave Transmitter
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I2Cn_STATEDescription
I2Cn_IF
Required Response
interaction
0x41
Repeated START
received
RSTART interrupt flag
(BUSHOLD interrupt
flag)
RXDATA
Receive and compare address
0x73
ADDR + R received
ADDR interrupt flag
ACK +
ACK will be sent, then DATA
TXDATA
RXDATA interrupt flag NACK
NACK will be sent, slave goes idle
(BUSHOLD interrupt
flag)
NACK +
CONT +
TXDATA
NACK will be sent, then DATA.
-
Data transmitted
TXBL interrupt flag
None
(TXC interrupt flag)
0xD5
Data transmitted, ACK ACK interrupt flag
received
(BUSHOLD interrupt
flag)
TXDATA DATA will be transmitted
0xDD
Data transmitted,
NACK received
NACK interrupt flag
(BUSHOLD interrupt
flag)
None
The slave goes idle
CONT + DATA will be transmitted
TXDATA
-
Stop received
SSTOP interrupt flag None
The slave goes idle
START START will be sent when bus becomes idle
-
Arbitration lost
ARBLOST interrupt None
The slave goes idle
flag
START START will be sent when the bus becomes idle
16.3.9.4 Slave Receiver
A slave receiver operation is started in the same way as a slave transmitter operation, with the exception
that the address transmitted by the master has the R/W bit cleared (W), indicating that the master wishes
to write to the slave. The slave then goes into slave receiver mode.
To receive data from the master, the slave should respond to the address with an ACK and make sure
space is available in the receive buffer. Transmission will then continue, and the slave will receive a
byte from the master.
If a NACK is sent without a CONT, the transmission is ended for the slave, and it goes idle. If the slave
issues both the NACK and CONT commands and has space available in the receive buffer, it will be
open for continuing reception from the master.
When a byte has been received from the master, the slave must ACK or NACK the byte. The responses
here are the same as for the reception of the address byte.
The master ends the transmission by sending a STOP or a repeated START. The SSTOP interrupt flag
is set when the master transmits a STOP condition. If the transmission is ended with a repeated START,
then the SSTOP interrupt flag in I2Cn_IF is not set.
Note
The SSTOP interrupt flag in I2Cn_IF will be set regardless of whether the slave is
participating in the transmission or not, as long as SLAVE in I2Cn_CTRL is set and a STOP
condition is detected
If arbitration is lost at any time during transmission, the ARBLOST interrupt flag in I2Cn_IF is set, the
bus is released and the slave goes idle.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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