UPD784938 Datasheet, PDF (206/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 7 REAL-TIME OUTPUT FUNCTION
7.4 Operation
When the port 0 function is specified as the real-time output port, the port 0 buffer register (P0H, P0L) contents are fetched
into the output latch and output to the port 0 pins in synchronization with the generation of one of the trigger conditions shown
in Table 7-2.
For example, the timer/event counter 1 timer counter 1 (TM1) and compare register (CR10, CR11) match signal (INTC10,
INTC11) can be selected as the output trigger generation source. In this case, the port 0 pin output data can be changed to the
P0H and P0L values using the value set in the CR10, CR11 beforehand as the timing interval. Combining this real-time output
port function with the macro service function enables the port 0 output pin output data to be changed sequentially at any interval
time (see 23.8 Macro Service Function).
If the INTP0 external interrupt pin is selected as the output trigger source, port 0 output can be obtained in synchronization
with an external event.
Table 7-2. Real-Time Output Port Output Triggers (when P0MH = P0ML = 1)
BYTE
0
0
0
1
1
1
RTPC
EXTR
0
1
1
0
1
1
TRGP0
0
0
1
0
0
1
Output Mode
4-bit real-time output
8-bit real-time output
P0H
P0L
INTC11
INTC11
INTC11
INTC10
INTC10 or INTP0
INTP0
INTC10
INTC10 or INTP0
INTP0
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Preliminary User’s Manual U13987EJ1V0UM00