
185
CHAPTER 8 16-BIT TIMER/EVENT COUNTER
6
5
4
3
2
1
0
7
Symbol
PM3
PM37 PM36 PM35 PM34 PM33 PM32 PM31 PM30
PM3n
0
1
Selects l/O mode of P3n pin (n = 0-7)
Output mode (output buffer ON)
Input mode (output buffer OFF)
FF23H FFH R/W
Address On reset R/W
(4) Port mode register 3 (PM3)
This register sets the input/output mode of port 3 in 1-bit units.
When the P30/TO0 pin is used as a timer output pin, set 0 to the PM30 bit of this register and the output latch
of the P30 pin.
PM3 is set by a 1-bit or 8-bit memory manipulation instruction.
This register is set to FFH when the RESET signal is input.
Figure 8-7. Format of Port Mode Register 3