IBM PD78081 Network Card User Manual


 
114
CHAPTER 8 CLOCK OUTPUT CONTROL CIRCUIT
PM37
7
PM36
6
PM35 PM34
4
PM33
3210
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 set port 3 input/output in 1-bit units.
When using the P35/PCL pin for clock output function, set PM35 and output latch of P35 to 0.
PM3 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets PM3 to FFH.
Figure 8-4. Port Mode Register 3 Format