NEC PD78056F User Manual

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CHAPTER 20 REAL-TIME OUTPUT PORT

(1) Real-time output buffer register (RTBL, RTBH)

Addresses of RTBL and RTBH are mapped individually in the Special function register (SFR) area as shown

in Figure 20-2.

When specifying 4 bits

2 channels as the operating mode, data are set individually in RTBL and RTBH.

When specifying 8 bits

1 channel as the operating mode, data are set to both RTBL and RTBH by writing

8-bit data to either RTBL or RTBH.

Table 20-2 shows operations during manipulation of RTBL and RTBH.

Figure 20-2. Real-time Output Buffer Register Configuration

Table 20-2. Operation in Real-time Output Buffer Register Manipulation

During Read

Note 1

During Write

Note 2

Higher 4 Bits

Lower 4 Bits

Higher 4 Bits

Lower 4 Bits

RTBL

RTBH

RTBL

Invalid

RTBL

RTBH

RTBL

RTBH

Invalid

RTBL

RTBH

RTBL

RTBH

RTBL

RTBH

RTBL

RTBH

RTBL

Notes 1. Only the bits set in the real-time output port mode can be read. When a bit set in the port mode

is read, 0 is read.

2. After setting data in the real-time output port, output data should be set in RTBL and RTBH by the

time a real-time output trigger is generated.

Operating Mode

Manipulated

8 bits

1 channel

4 bits

2 channels

Higher
4 Bits

Lower
4 Bits

RTBL

RTBH

FF30H

FF31H