CHAPTER 11 BUZZER OUTPUT CONTROLLER
189
User’s Manual U11302EJ4V0UM
(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, set PM36 and the 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 11-3. Format of Port Mode Register 3
7
6
5
4
3
2
1
0
PM37 PM36 PM35 PM34 PM33 PM32 PM31 PM30
Symbol
PM3
Address
FF23H
After reset
FFH
R/W
R/W
PM3n
0
1
P3n pin I/O mode selection (n = 0 to 7)
Output mode (output buffer on)
Input mode (output buffer off)