NEC uPD78056Y User Manual

Page 264

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264

CHAPTER 13 BUZZER OUTPUT CONTROL CIRCUIT

PM37

7

PM36

6

PM35 PM34

4

PM33

3

2

1

0

FF23H

Address

PM3

Symbol

PM32 PM31 PM30

5

FFH

After

Reset

R/W

R/W

PM3n

0

1

P3n Pin Input/Output Mode Selection (n=0 to 7)

Output mode (output buffer ON)

Input mode (output buffer OFF)

(2) Port mode register 3 (PM3)

This register sets port 3 input/output in 1-bit units.

When using the P36/BUZ pin for buzzer output function, set PM36 and output latch of P36 to 0.

PM3 is set with a 1-bit or 8-bit memory manipulation instruction.

RESET input sets PM3 to FFH.

Figure 13-3. Port Mode Register 3 Format

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