s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 122

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports (PORTS)
Figure 12-12
When bit DDRDx is a 1, reading address $0003 reads the PTDx data latch. When bit DDRDx is a 0,
reading address $0003 reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit.
12.6 Port E
Port E is a 2-bit special function port that shares its pins with the enhanced serial communications
interface module (ESCI).
12.6.1 Port E Data Register
The port E data register contains a data latch for each of the port E pins.
122
Alternative Function:
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
DDRD
shows the port D I/O logic.
Bit
0
1
Address:
Reset:
Read:
Write:
READ DDRD ($0007)
WRITE DDRD ($0007)
WRITE PTD ($0003)
READ PTD ($0003)
PTD
Bit
X
X
$0008
Bit 7
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
0
Figure 12-13. Port E Data Register (PTE)
Input, Hi-Z
I/O Pin
Output
Mode
= Unimplemented
Table 12-4. Port D Pin Functions
RESET
Figure 12-12. Port D I/O Circuit
6
0
Accesses to DDRD
Table 12-4
5
0
Read/Write
DDRDx
DDRD[1:0]
DDRD[1:0]
PTDx
Unaffected by reset
4
0
summarizes the operation of the port D pins.
3
0
PTD[1:0]
Read
Pin
Accesses to PTD
2
0
PTE1
RXD
PTD[1:0]
PTD[1:0]
1
Freescale Semiconductor
Write
PTDx
(1)
PTE0
Bit 0
TXD