NEC PD78F9488 - Manual (Page 242)

CHAPTER 12 SERIAL INTERFACE 1A0
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User’s Manual U15331EJ4V1UD
In 6-byte transmission (bit 6 (ARLD0) and bit 7 (RE0) of automatic data transmit/receive control register 0
(ADTC0) are 0) in basic transmit mode, buffer RAM operates as follows.
(i) Before transmission (refer to Figure 12-12 (a))
After any data has been written to SIO1A0 (start trigger: this data is not transferred), transmit data 1
(T1) is transferred from the buffer RAM to SIO1A0. When transmission of the first byte is completed,
ADTP0 is decremented. Then transmit data 2 (T2) is transferred from the buffer RAM to SIO1A0.
(ii) 4th byte transmission point (refer to Figure 12-12 (b))
Transmission of the third byte is completed, and transmit data 4 (T4) is transferred from the buffer
RAM to SIO1A0. When transmission of the fourth byte is completed, ADTP0 is decremented.
(iii) Completion of transmission/reception (refer to Figure 12-12 (c))
When transmission of the sixth byte is completed, the interrupt request flag (CSIIF10) is set
(INTCSI10 generation).
Figure 12-12. Buffer RAM Operation in 6-Byte Transmission (in Basic 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)
FFAFH
FFA5H
FFA0H
SIO1A0
0 CSIIF10
5 ADTP0
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