
CHAPTER 18 CLOCKED SERIAL INTERFACE A (CSIA) WITH AUTOMATIC TRANSMIT/RECEIVE FUNCTION
User’s Manual U16890EJ1V0UD
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(2) Automatic transmission/reception communication operation
(a) Automatic transmission/reception mode
Automatic transmission/reception can be performed using buffer RAM.
The data stored in the buffer RAM is output from the SOAn pin via the SIOAn register in synchronization
with the SCKAn pin falling edge by performing (a) and (b) in
(1) Automatic transmit/receive data
setting
.
The data is then input from the SIAn pin via the SIOAn register in synchronization with the serial clock
falling edge of the SCKAn pin and the receive data is stored in the buffer RAM in synchronization with the
rising edge 1 clock later.
Data transfer ends if the CSISn.TSFn bit is cleared to 0 when any of the following conditions is met.
Reset by clearing the CSIMAn.CSIAEn bit to 0
Transfer of 1 byte is complete by setting the CSITn.ATSTPn bit to 1
Transfer of the range specified by the ADTPn register is complete
At this time, a transmission/reception completion interrupt request signal (INTCSIAn) is generated except
when the CSIAEn bit = 0.
If a transfer is terminated in the middle, transfer starting from the remaining data is not possible. Read
the ADTCn register to confirm how much of the data has already been transferred, set the transfer data
again, and perform (a) and (b) in
(1) Automatic transmit/receive data setting
.
Figure 18-5 shows the operation timing in automatic transmission/reception mode and Figure 18-6 shows
the operation flowchart. Figure 18-7 shows the operation of the buffer RAM when 6 bytes of data are
transmitted/received.
Remark
n = 0, 1