W77E468 查看數據表（PDF） - Winbond

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W77E468

8 BIT MICROCONTROLLER

Winbond 

Preliminary W77E468

Data Pointers:

The original 8052 had only one 16-bit Data Pointer (DPL, DPH). In the W77E468, there is an

additional 16-bit Data Pointer (DPL1, DPH1). This new Data Pointer uses two SFR locations which

were unused in the original 8052. In addition there is an added instruction, DEC DPTR (op-code

A5H), which helps in improving programming flexibility for the user.

Power Management:

Like the standard 80C52, the W77E468 also has IDLE and POWER DOWN modes of operation. The

W77E468 provides a new Economy mode which allow user to switch the internal clock rate divided by

either 4, 64 or 1024. In the IDLE mode, the clock to the CPU core is stopped while the timers, serial

ports and interrupts clock continue to operate. In the POWER DOWN mode, all the clock are stopped

and the chip operation is completely stopped. This is the lowest power consumption state.

On-chip Data SRAM:

The W77E468 has 1K Bytes of data space SRAM which is read/write accessible and is memory

mapped. This on-chip MOVX SRAM is reached by the MOVX instruction. It is not used for executable

program memory. There is no conflict or overlap among the 256 bytes Scratchpad RAM and the 1K

Bytes MOVX SRAM as they use different addressing modes and separate instructions. The on-chip

MOVX SRAM is enabled by setting the DME0 bit in the PMR register. After a reset, the DME0 bit is

cleared such that the on-chip MOVX SRAM is disabled, and all data memory spaces 0000H−FFFFH

access to the external memory.

MEMORY ORGANIZATION

The W77E468 separates the memory into two separate sections, the Program Memory and the Data

Memory. The Program Memory is used to store the instruction op-codes, while the Data Memory is

used to store data or for memory mapped devices.

Program Memory:

The Program Memory on the W77E468 can be up to 64Kbytes long. There is also on-chip ROM

which can be used similarly to that of the 8052, except that the ROM size is 32Kbytes. All

instructions are fetched for execution from this memory area. The MOVC instruction can also access

this memory region. Exceeding the maximum address of on-chip ROM will access to the external

memory.

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