C165 查看數據表（PDF） - Siemens AG
零件编号
产品描述 (功能)
比赛名单
C165 Datasheet PDF : 49 Pages
| |||
C165
Pin Definitions and Functions (cont’d)
Symbol
P4.0 –
P4.7
RD
WR/
WRL
READY
ALE
EA
Pin
No.
25 - 28,
31 - 34
25
...
34
35
36
37
38
39
Input (I) Function
Output (O)
I/O
Port 4 is an 8-bit bidirectional I/O port. It is bit-wise
programmable for input or output via direction bits. For a pin
configured as input, the output driver is put into high-
impedance state.
In case of an external bus configuration, Port 4 can be used to
output the segment address lines:
O
P4.0
A16
Least Significant Segment Addr. Line
...
...
...
...
O
P4.7
A23
Most Significant Segment Addr. Line
O
External Memory Read Strobe. RD is activated for every
external instruction or data read access.
O
External Memory Write Strobe. In WR-mode this pin is
activated for every external data write access. In WRL-mode
this pin is activated for low byte data write accesses on a 16-
bit bus, and for every data write access on an 8-bit bus. See
WRCFG in register SYSCON for mode selection.
I
Ready Input. When the Ready function is enabled, a high
level at this pin during an external memory access will force
the insertion of memory cycle time waitstates until the pin
returns to a low level.
O
Address Latch Enable Output. Can be used for latching the
address into external memory or an address latch in the
multiplexed bus modes.
I
External Access Enable pin. A low level at this pin during and
after Reset forces the C165 to begin instruction execution out
of external memory. A high level forces execution out of the
internal ROM. The C165 must have this pin tied to ‘0’.
Semiconductor Group
6
Share Link: 