Automatic Transmit/Receive Interval - NEC mPD780208 Subseries User Manual

(5) Automatic transmit/receive interval

When the automatic transmit/receive function is used, one byte is transmitted/received and then the buffer
RAM is read/written; therefore an interval is inserted before the next transmission/reception.
When the automatic transmit/receive function is performed using an internal clock, since the read/write
operations from/to the buffer RAM are done in parallel with CPU processing, the interval depends on the
CPU processing at the timing of the serial clock's eighth rising-edge and the value set in the automatic
data transmit/receive interval specification register (ADTI). Whether or not the interval depends on ADTI
can be selected by setting bit 7 (ADTI7) of ADTI.
When ADTI7 is set to 0, the interval depends only on the CPU processing. When ADTI7 is set to 1, the
interval is the value determined by the contents of ADTI or other value determined by CPU processing,
whichever is greater.
When the automatic transmit/receive function is performed using an external clock, the clock must be
selected so that the interval is longer than the value shown in (b).
SCK1
SO1 D7 D6 D5 D4 D3 D2 D1 D0
SI1 D7 D6 D5 D4 D3 D2 D1 D0
CSIIF1
CSIIF1: Interrupt request flag
296
CHAPTER 14 SERIAL INTERFACE CHANNEL 1
Figure 14-23. Automatic Transmit/Receive Interval
Interval
User's Manual U11302EJ4V0UM
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0