MC68HC908QL4 Datasheet, PDF (114/222 Pages) Motorola, Inc – Microcontrollers

Input/Output Ports (PORTS)
PTAPUE[5:0] — Port A Input Pullup/Down Enable Bits
These read/write bits are software programmable to enable pullup/down devices on port A pins.
1 = Corresponding port A pin configured to have internal pullup/down if its DDRA bit is set to 0
0 = Pullup/down device is disconnected on the corresponding port A pin regardless of the state of
its DDRA bit
12.2.4 Port A Summary Table
The following table summarizes the operation of the port A pins when used as a general-purpose
input/output pins.
Table 12-1. Port A Pin Functions
PTAPUE
Bit
1
0
X
DDRA
Bit
0
0
1
PTA
Bit
X⁽¹⁾
X
X
I/O Pin
Mode
Input, V_Pull(2)
Input, Hi-Z⁽⁴⁾
Output
Accesses to DDRA
Read/Write
DDRA5–DDRA0
DDRA5–DDRA0
DDRA5–DDRA0
1. X = don’t care
2. I/O pin pulled to V_Pull (V_DD or V_SS) by internal pullup or pulldown.
3. Writing affects data register, but does not affect input.
4. Hi-Z = high impedance
5. Output does not apply to PTA2
Accesses to PTA
Read
Write
Pin
PTA5–PTA0⁽³⁾
Pin
PTA5–PTA0⁽³⁾
PTA5–PTA0 _{PTA5–PTA0}⁽⁵⁾
12.3 Port B
Port B is an 8-bit special function port that shares its pins with the 2-channel timer interface module (TIM)
(see Chapter 15 Timer Interface Module (TIM)), the 10-bit ADC (see Chapter 3 Analog-to-Digital
Converter (ADC10) Module), and the slave LIN interface controller (SLIC) module (see Chapter 14 Slave
LIN Interface Controller (SLIC) Module).
Each port B pin also has a software configurable pullup device if the corresponding port pin is configured
as an input port.
12.3.1 Port B Data Register
The port B data register (PTB) contains a data latch for each of the port B pins.
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PTB7
Write:
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0
Reset:
Unaffected by reset
Figure 12-5. Port B Data Register (PTB)
PTB[7:0] — Port B Data Bits
These read/write bits are software programmable. Data direction of each port B pin is under the control
of the corresponding bit in data direction register B. Reset has no effect on port B data.
MC68HC908QL4 • MC68HC908QL3 • MC68HC908QL2 Data Sheet, Rev. 4
114
Freescale Semiconductor