NEC PD78052 User Manual page 427

In 6-byte transmission (ARLD=1, RE=0) in repeat transmit mode, buffer RAM operates as follows.
(i) Before transmission (Refer to Figure 18-16 (a))
After any data has been written to serial I/O shift register 1 (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, automatic data transmit/receive address pointer (ADTP) 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 18-16 (b))
When transmission of the sixth byte is completed, the interrupt request flag (CSIIF1) is not set. The
first pointer value is set to ADTP again.
(iii) 7th byte transmission point (Refer to Figure 18-16 (c))
Transmit data 1 (T1) is transferred from the buffer RAM to SIO1 again. When transmission of the
first byte is completed, ADTP is decremented. Then transmit data 2 (T2) is transferred from the buffer
RAM to SIO1.
Figure 18-16. Buffer RAM Operation in 6-Byte Transmission
FADFH
FAC5H Transmit data 1 (T1)
Transmit data 2 (T2)
Transmit data 3 (T3)
Transmit data 4 (T4)
Transmit data 5 (T5)
FAC0H Transmit data 6 (T6)
CHAPTER 18 SERIAL INTERFACE CHANNEL 1
(in Repeat Transmit Mode) (1/2)
(a) Before transmission
SIO1
5 ADTP
–1
0 CSIIF1
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