NEC mPD780065 Series Preliminary User's Manual page 241

In 6-byte transmission (bit 6 (ARLD0) and bit 7 (RE0) of the automatic data transmit/receive control register
(ADTC0) are 1 and 0, respectively) in repeat transmit mode, buffer RAM operates as follows.
(i) Before transmission (refer to Figure 14-15 (a))
After any data has been written to SIO1 (start trigger: this data is not transferred), transmit data 1
(T1) is transferred from the buffer RAM to SIO1. When transmission of the first byte is completed,
ADTP0 is decremented. Then transmit data 2 (T2) is transferred from the buffer RAM to SIO1.
(ii) Upon completion of transmission of 6 bytes (refer to Figure 14-15 (b))
When transmission of the sixth byte is completed, the interrupt request flag (CSIIF1) is not set. The
previous pointer value is assigned to the ADTP0.
(iii) 7th byte transmission point (refer to Figure 14-15 (c))
Transmit data 1 (T1) is transferred from the buffer RAM to SIO1 again. When transmission of the
first byte is completed, ADTP0 is decremented. Then transmit data 2 (T2) is transferred from the
buffer RAM to SIO1.
Figure 14-15. Buffer RAM Operation in 6-Byte Transmission (in Repeat Transmit Mode) (1/2)
FADFH
FAC5H Transmit data 1 (T1)
Transmit data 2 (T2)
Transmit data 3 (T3)
Transmit data 4 (T4)
Transmit data 5 (T5)
Transmit data 6 (T6)
FAC0H
CHAPTER 14 SERIAL INTERFACE (SIO1)
(a) Before transmission
Preliminary User's Manual U13420EJ2V0UM00
SIO1
5 ADTP0
_ 1
0 CSIIF1
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