NEC PD78058FY(A) - Manual (Page 421)

421
CHAPTER 18 SERIAL INTERFACE CHANNEL 1
In 6-byte transmission (ARLD = 1, RE = 0) in repeat transmit mode, internal buffer RAM operates as follows.
(i) Before transmission (See 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 internal 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 internal buffer RAM to SIO1.
(ii) Upon completion of transmission of 6 bytes (See Figure 18-16 (b).)
Even when sending of the 6th byte is completed, the interrupt request flag (CSIIF1) is not set. The
initial pointer value is reset in ADTP.
(iii) 7th byte transmission point (See Figure 18-16 (c).)
Transmit data 1 (T1) is transferred from the internal 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 internal buffer RAM to SIO1.
Figure 18-16. Internal Buffer RAM Operation in 6-Byte Transmission
(in Repeat Transmit Mode) (1/2)
(a) Before transmission
Transmit data 1 (T1)
Transmit data 2 (T2)
Transmit data 3 (T3)
Transmit data 4 (T4)
Transmit data 5 (T5)
Transmit data 6 (T6)
FADFH
FAC5H
FAC0H
SIO1
0 CSIIF1
5 ADTP
–1