NEC uPD78056Y - Manual (Page 416)

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CHAPTER 18 SERIAL INTERFACE CHANNEL 1
(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 at
maximum). The transmit data should be in the order from high-order address to low-order address.
<2> Set to the automatic data transmit/receive address pointer (ADTP) the value obtained by
subtracting 1 from the number of transmit data bytes.
(b) Automatic transmit/receive mode setting
<1> Set bit 7 (CSIE1) to 1 and bit 5 (ATE) to 1 of the 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 a data transmit/receive interval in the automatic data transmit/receive interval specify register
(ADTI).
<4> Write any value to the serial I/O shift register 1 (SIO1) (transfer start trigger).
Caution Writing any value to SIO1 orders the start of automatic transmit/receive operation and
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 with 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 with 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.