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CHAPTER 14
SERIAL INTERFACE SIO1
User’s Manual U12790EJ2V0UD
(2) Automatic transmit/receive data setting
(a) Transmit data setting
<1>
Write transmit data from the least significant address FAC0H of buffer RAM (up to FADFH). The
transmit data should be in the order of higher address to lower address.
<2>
Set the value obtained by subtracting 1 from the number of transmit data bytes to the automatic
data transmit/receive address pointer (ADTP).
(b) Automatic transmit/receive mode setting
<1>
Set bit 7 (CSIE1) and bit 5 (ATE) of serial operating mode register 1 (CSIM1) to 1.
<2>
Set bit 7 (RE) of the automatic data transmit/receive control register (ADTC) to 1.
<3>
Set the data transmit/receive interval in the automatic data transmit/receive interval specification
register (ADTI).
<4>
Write any value to serial I/O shift register 1 (SIO1) (transfer start trigger).
Caution
Writing any value to SIO1 orders the start of automatic transmit/receive operation; the
written value has no meaning.
The following operations are automatically carried out when (a) and (b) are carried out.
 After the buffer RAM data specified by ADTP is transferred to SIO1, transmission is carried out (start
of automatic transmission/reception).
 The received data is written to the buffer RAM address specified by ADTP.
 ADTP is decremented and the next data transmission/reception is carried out. Data transmission/
reception continues until the ADTP decremental output becomes 00H and address FAC0H data is
output (end of automatic transmission/reception).
 When automatic transmission/reception is terminated, bit 3 (TRF) of ADTC is cleared to 0.