Input/Output (I/O) Ports
Technical Data MC68HC908AB32 — Rev. 1.0
332 Input/Output (I/O) Ports MOTOROLA
17.8.3 Port F Input Pullup Enable Register (PTFPUE)
The port F input pullup enable register (PTFPUE) controls the input
pullup device for each of the eight port F pins. Each bit is individually
configurable and requires that the data direction register, DDRF, bit be
configured as an input. Each pullup is automatically and dynamically
disabled when a port bit’s DDRF is configured for output mode.
PTFPUE[7:0] — Port F Input Pullup Enable Bits
These writable bits are software programmable to enable pullup
devices on an input port pin.
1 = Corresponding port F pin configured to have internal pullup
0 = Corresponding port F pin internal pullup disconnected
17.9 Port G
Port G is a 3-bit special-function port that shares all three of its pins with
the keyboard interrupt (KBI) module.
17.9.1 Port G Data Register (PTG)
The port G data register (PTG) contains a data latch for each of the three
port G pins.
Address: $003E
Bit 7 654321Bit 0
Read:
PTFPUE7 PTFPUE6 PTFPUE5 PTFPUE4 PTFPUE3 PTFPUE2 PTFPUE1 PTFPUE0
Write:
Reset: 0 0000000
Figure 17-21. Port F Input Pullup Enable Register (PTFPUE)