Registers Controlling Port Function - NEC 78K0 User Manual

4.3 Registers Controlling Port Function

Port functions are controlled by the following three types of registers.
• Port mode registers (PM0, PM1, PM3, PM6, PM7, PM12)
• Port registers (P0 to P3, P6, P7, P12, P13)
• Pull-up resistor option registers (PU0, PU1, PU3, PU7, PU12)
(1) Port mode registers (PM0, PM1, PM3, PM6, PM7, and PM12)
These registers specify input or output mode for the port in 1-bit units.
These registers can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets these registers to FFH.
When port pins are used as alternate-function pins, set the port mode register and output latch as shown in Table
4-5.
Symbol 7 6
PM0 1 1
7 6
PM1
PM17 PM16
7 6
PM3 1 1
7 6
PM6 1 1
7 6
PM7
1 1
7 6
PM12 1 1
PMmn
0 Output mode (output buffer on)
1 Input mode (output buffer off)
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CHAPTER 4 PORT FUNCTIONS
Figure 4-16. Format of Port Mode Register
5 4 3
1 1 1
5 4 3
PM15 PM14 PM13
5 4 3
1 1 PM33
5 4 3
1 1 PM63
5 4 3
1 1 PM73
5 4 3
1 1 1
Pmn pin I/O mode selection
(m = 0, 1, 3, 6, 7, 12; n = 0 to 7)
User's Manual U16227EJ2V0UD
2 1 0
1 PM01 PM00
2 1 0
PM12 PM11 PM10
2 1 0
PM32 PM31 PM30
2 1 0
PM62 PM61 PM60
2 1 0
PM72 PM71 PM70
2 1 0
1 1 PM120
Address After reset R/W
FF20H FFH R/W
FF21H FFH R/W
FF23H FFH R/W
FF26H FFH R/W
FF27H FFH R/W
FF2CH FFH R/W