NEC PD789488 User Manual page 235

Pd789489 subseries 8-bit single-chip microcontrollers
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(2)
Automatic transmit/receive data setting
(a) Transmit data setting
<1>
Write transmit data from the least significant address FFA0H of buffer RAM (up to FFAFH). The
transmit data should be in the order from higher address to lower address.
<2>
Set the value obtained by subtracting 1 from the number of transmit data bytes to automatic data
transmit/receive address pointer 0 (ADTP0).
(b) Automatic transmit/receive mode setting
<1>
Set bit 7 (CSIE10) and bit 5 (ATE0) of serial operation mode register 1A0 (CSIM1A0) to 1.
<2>
Set bit 7 (RE0) of automatic data transmit/receive control register 0 (ADTC0) to 1.
<3>
Set the data transmit/receive interval in automatic data transmit/receive interval specification
register 0 (ADTI0).
<4>
Write any value to serial I/O shift register 1A0 (SIO1A0) (transfer start trigger).
Caution
Writing any value to SIO1A0 orders the start of automatic transmission/reception
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 ADTP0 is transferred to SIO1A0, transmission is carried out
(start of automatic transmission/reception).
The received data is written to the buffer RAM address specified by ADTP0.
ADTP0 is decremented and the next data transmission/reception is carried out.
transmission/reception continues until the ADTP0 decremental output becomes 00H and address
FFA0H data is output (end of automatic transmission/reception).
When automatic transmission/reception is terminated, bit 3 (TRF0) of ADTC0 is cleared to 0.
CHAPTER 12 SERIAL INTERFACE 1A0
User's Manual U15331EJ4V1UD
Data
235

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