參數(shù)資料
型號: μPD784225
廠商: NEC Corp.
英文描述: 16 Bit Single Chip Microcontrollers(16 位單片微控制器)
中文描述: 16位單片機微控制器(16位單片微控制器)
文件頁數(shù): 48/68頁
文件大?。?/td> 384K
代理商: ΜPD784225
48
m
PD784224, 784225
9. LOCAL BUS INTERFACE
The local bus interface can connect an external memory or I/O (memory mapped I/O) and support a memory
space of 1 MByte (refer to
Figure 9-1
).
Figure 9-1. Example of Local Bus Interface (Multiplexed bus)
μ
PD784225
RD
WR
A8-A19
ASTB
AD0-AD7
V
DD1
Address latch
LE
Q0-Q7
D0-D7
OE
SRAM
CS
OE
WE
I/O1-I/O8
A0-A19
Data bus
Address bus
9.1 Memory Expansion
External program and data memory can be connected in two stages: 256K bytes and 1 Mbytes.
To connect the external memory, ports 4 through 6 are used.
The external memory is connected by using a time-division address/data bus. The number of ports used when
the external memory is connected can be reduced in this mode.
9.2 Programmable Wait
Wait state(s) can be inserted to the memory space (00000H through FFFFFH) while the RD and WR signals are
active.
In addition, there is an address wait function that extends the active period of the ASTB signal to gain the address
decode time.
9.3 External Access Status Function
An active low external access status signal is output from the P37/EXA pin. This signal notifies other devices
connected to the external bus of the external access status, to disable data output to the external bus from other
devices, or enables reception.
The external access status signal is output during external access.
相關(guān)PDF資料
PDF描述
μPD784225Y 16 Bit Single Chip Microcontrollers(16 位單片微控制器)
μPD78F4216Y 8/16 Bit RISC Microcontrollers(8/16位RISC微控制器)
μPD78F9177Y 8 Bit Single Chip Microcontrollers(8 位單片微控制器)
μPG173TA L-Band PA Driver Amplifier(L波段PA驅(qū)動放大器)
μPG181GR GaAs MMIC DBS Twin IF Switch(砷化鎵微波集成電路)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PD784976A 制造商:NEC 制造商全稱:NEC 功能描述:16-Bit Single-Chip Microcontroller
PD7869 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Optoelectronic
PD78F0134 制造商:NEC 制造商全稱:NEC 功能描述:8-Bit Single-Chip Microcontrollers
PD78F0134(A) 制造商:NEC 制造商全稱:NEC 功能描述:8-Bit Single-Chip Microcontrollers
PD78F0134(A1) 制造商:NEC 制造商全稱:NEC 功能描述:8-Bit Single-Chip Microcontrollers