Chapter 21 Real-Time Output Port; Real-Time Output Port Functions; Real-Time Output Port Block Diagram; Real-Time Output Port Configuration - NEC PD78076 User Manual

21.1 Real-Time Output Port Functions

Data set previously in the real-time output buffer register can be transferred to the output latch by hardware
concurrently with timer interrupt request or external interrupt request generation, then output externally. This is
called the real-time output function. The pins that output data externally are called real-time output ports.
By using a real-time output, a signal which has no jitter can be output. This port is therefore suitable for control
of stepping motors, etc.
Port mode/real-time output port mode can be specified bit-wise.

21.2 Real-Time Output Port Configuration

The real-time output port consists of the following hardware.
Register
Control register
BYTE
INTP2
Output Trigger
INTTM1
Control Circuit
INTTM2

CHAPTER 21 REAL-TIME OUTPUT PORT

Table 21-1. Real-time Output Port Configuration
Item
Real-time output buffer register (RTBL, RTBH)
Port mode register 12 (PM12)
Real-time output port mode register (RTPM)
Real-time output port control register (RTPC)
Figure 21-1. Real-time Output Port Block Diagram
Real-time Output
Port Control
Register
EXTR
Real-time Output
Buffer Register
Higher 4 Bits
(RTBH)
Output Latch
P127
Configuration
Internal Bus
Port Mode
Register 12
(PM12)
Real-time Output
Buffer Register
Lower 4 Bits
(RTBL)
P120
Real-time Output port
Mode Register (RTPM)
495