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• Note on ICDR Read at end of Master Reception
To halt reception after completion of a receive operation in master receive mode, set the TRS
bit to 1 and write 0 to BBSY and SCP in ICCR. This changes the SDA pin from low to high
when the SCL pin is high, and generates the stop condition. After this, receive data can be read
by means of an ICDR read, but if data remains in the buffer the ICDRS receive data will not be
transferred to ICDR, and so it will not be possible to read the second byte of data. If it is
necessary to read the second byte of data, issue the stop condition in master receive mode (i.e.
with the TRS bit cleared to 0). When reading the receive data, first confirm that the BBSY bit
in ICCR is cleared to 0, the stop condition has been generated, and the bus has been released,
then read ICDR with TRS cleared to 0. Note that if the receive data (ICDR data) is read in the
interval between execution of the instruction for issuance of the stop condition (writing of 0 to
BBSY and SCP in ICCR) and the actual generation of the stop condition, the clock may not be
output correctly in subsequent master transmission.
• Notes on Start Condition Issuance for Retransmission
Depending on the timing combination with the start condition issuance and the subsequently
writing data to ICDR, it may not be possible to issue the retransmission and the data
transmission after retransmission condition issuance.
After start condition issuance is done and determined the start condition, write the transmit
data to ICDR, as shown below. Figure 15.17 shows the timing of start condition issuance for
retransmission, and the timing for subsequently writing data to ICDR, together with the
corresponding flowchart.
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