MC908AZ32ACFUE Datasheet, PDF (259/324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Port H
When bit DDRGx is a logic 1, reading address $000A reads the PTGx data latch. When bit DDRGx is a
logic 0, reading address $000A reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 23-7 summarizes the operation of the port G pins.
Table 23-7. Port G Pin Functions
DDRG
Bit
PTG
Bit
I/O Pin
Mode
Accesses to
DDRG
Read/Write
0
X
Input, Hi-Z DDRG[2:0]
1
X
Output
DDRG[2:0]
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
Accesses to PTG
Read
Pin
PTG[2:0]
Write
PTG[2:0]⁽¹⁾
PTG[2:0]
23.9 Port H
Port H is a 2-bit special function port that shares all of its pins with the keyboard interrupt module (KBD).
Note that Port H is only available on 64-pin package options.
23.9.1 Port H Data Register
The port H data register contains a data latch for each of the two port H pins.
Address:
Read:
Write:
Reset:
Alternate
Function:
$000B
Bit 7
0
R
R
6
5
4
3
2
0
0
0
0
0
R
R
R
R
R
Unaffected by Reset
= Reserved
Figure 23-23. Port H Data Register (PTH)
1
PTH1
KBD4
Bit 0
PTH0
KBD3
PTH[1:0] — Port H Data Bits
These read/write bits are software programmable. Data direction of each port H pin is under the control
of the corresponding bit in data direction register H. Reset has no effect on PTH[1:0].
KBD[4:3] — Keyboard Wake-up pins
The keyboard interrupt enable bits, KBIE[4:3], in the keyboard interrupt control register, enable the port
H pins as external interrupt pins (See Chapter 22 Keyboard Module (KBD)).
MC68HC908AZ32A Data Sheet, Rev. 2
Freescale Semiconductor
259