s908ab32ag0cfue Freescale Semiconductor, Inc, s908ab32ag0cfue Datasheet - Page 336

• Manufacturer Part Number: s908ab32ag0cfue
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports
Technical Data
336
NOTE:
Address:
DDRH[1:0] — Data Direction Register H Bits
Avoid glitches on port H pins by writing to the port H data register before
changing data direction register H bits from 0 to 1.
the port H I/O logic.
When DDRHx is a logic 1, reading address $000B reads the PTHx data
latch. When DDRHx is a logic 0, reading address $000B reads the
voltage level on the pin. The data latch can always be written, regardless
of the state of its data direction bit.
Table 17-6
Reset:
Read:
Write:
These read/write bits control port H data direction. Reset clears
DDRH[1:0], configuring all port H pins as inputs.
1 = Corresponding port H pin configured as output
0 = Corresponding port H pin configured as input
READ DDRH ($000F)
WRITE DDRH ($000F)
WRITE PTH ($000B)
READ PTH ($000B)
$000F
Bit 7
Figure 17-26. Data Direction Register H (DDRH)
0
0
summarizes the operation of the port H pins.
Input/Output (I/O) Ports
6
0
0
Figure 17-27. Port H I/O Circuit
RESET
5
0
0
DDRHx
PTHx
4
0
0
3
0
0
MC68HC908AB32
Freescale Semiconductor
Figure 17-27
2
0
0
DDRH1
1
0
—
KBI
shows
DDRH0
Rev. 1.1
Bit 0
0
PTHx