UPD784224 Datasheet, PDF (33/92 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784224, 784225, 784224Y, 784225Y
7.3 Real-Time Output Port
The real-time output function is to transfer data set in advance to the real-time output buffer register to the output
latch as soon as the timer interrupt or external interrupt has occurred in order to output the data to an external device.
The pins that output the data to the external device constitute a port called a real-time output port.
Because the real-time output port can output signals without jitter, it is ideal for controlling a stepping motor.
Figure 7-5. Block Diagram of Real-Time Output Port
RTPOE BYTE
Internal bus
Real-time output port
control register (RTPC)
EXTR
INTP2TRG
INTTM1
INTTM2
Output trigger
controller
Higher 4 bits of
real-time output
buffer register
(RTBH)
Lower 4 bits of
real-time output
buffer register
(RTBL)
Real-time output
port mode register
(RTPM)
Port 12 output latch
Real-time output port output latch
P127······································ P120 RTP7······································ RTP0
RTPOE bit
P12n/RTPn pin output (n = 0 to 7)
PR1T2P77/······································
P120/
RTP0
Data Sheet U12376EJ1V0DS00
33