MC68HC908QY4A_10 Datasheet, PDF (106/200 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Input/Output Ports (PORTS)
12.3.4 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_DD(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_DD by internal pullup.
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⁾
12.4 Port B
Port B is an 8-bit special function port that shares two of its pins with the 10-bit ADC (see Chapter 3
Analog-to-Digital Converter (ADC10) Module).
Each port B pin also has a software configurable pullup device if the corresponding port pin is configured
as an input port.
12.4.1 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.
MC68HC908QYA/QTA Family Data Sheet, Rev. 3
106
Freescale Semiconductor