NEC PD78F9488 - Manual (Page 246)

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 1 and 0, respectively) in repeat transmit mode, buffer RAM operates as follows.
(i) Before transmission (refer to Figure 12-15 (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) Upon completion of transmission of 6 bytes (refer to Figure 12-15 (b))
When transmission of the sixth byte is completed, the interrupt request flag (CSIIF10) is not set. The
previous pointer value is assigned to the ADTP0.
(iii) 7th byte transmission point (refer to Figure 12-15 (c))
Transmit data 1 (T1) is transferred from the buffer RAM to SIO1A0 again. When transmission of the
first byte is completed, ADTP0 is decremented. Then transmit data 2 (T2) is transferred from the
buffer RAM to SIO1A0.
Figure 12-15. 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)
FFAFH
FFA5H
FFA0H
SIO1A0
0 CSIIF10
5 ADTP0
_1