NEC uPD78P078 - Manual (Page 454)

454
CHAPTER 19 SERIAL INTERFACE CHANNEL 1
(5) Automatic transmit/receive interval time
When using the automatic transmit/receive function, the read/write operations from/to the buffer RAM are
performed after transmitting/receiving one byte. Therefore, an interval is inserted before the next transmit/
receive.
Since the read/write operations from/to the buffer RAM are performed in parallel with the CPU processing
when using the automatic transmit/receive function by the internal clock, the interval depends on the value
which is set in the automatic transmit/receive interval specification register (ADTI) and the CPU processing
at the rising edge of the eighth serial clock. Whether it depends on the ADTI or not can be selected by the
setting of its bit 7 (ADTI7). When it is set to 0, the interval depends only on the CPU processing. When
it is set to 1, the interval depends on the contents of the ADTI or CPU processing, whichever is greater.
When the automatic transmit/receive function is used by an external clock, it must be selected so that the
interval may be longer than the value indicated by paragraph (b).
Figure 19-23. Automatic Data Transmit/Receive Interval
CSIIF1: Interrupt request flag
SCK1
SO1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
CSIIF1
SI1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
Interval