W79E201 Datasheet, PDF (8/87 Pages) Winbond – 8-BIT MICROCONTROLLER

W79E201
Interrupts
The Interrupt structure in the W79E201 is slightly different from that of the standard 8052. Due to the
presence of additional features and peripherals, the number of interrupt sources and vectors has been
increased. The W79E201 provides 8 interrupt resources with two priority levels, including 2 external
interrupt sources, 3 timer interrupts, 1 serial I/O interrupt, 1 ADC interrupt and 1 watch dog timer
interrupt.
Power Management
Like the standard 80C52, the W79E201 also has IDLE and POWER DOWN modes of operation. In
the POWER DOWN mode, all of the clocks of peripheral are stopped and the chip operation is
completely stopped. This is the lowest power consumption state.
7. MEMORY ORGANIZATION
The W79E201 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 standard 8052 can only be addressed to 64 Kbytes long. All instructions
are fetched for execution from this memory area. The MOVC instruction can also access this memory
region. There is an auxiliary 4KB Flash EPROM bank (LD Flash EPROM) resided user loader
program for In-System Programming (ISP). The AP Flash EPROM allows serial or parallel download
according to user loader program in LD Flash EPROM.
Data Memory
The W79E201 can access up to 64Kbytes of external Data Memory. This memory region is accessed
by the MOVX instructions. Any MOVX directed to the space between 0000H and FFFFH goes to the
expanded bus on Port 0 and 2. This is the default condition. In addition, the W79E201 has the
standard 256 bytes of on-chip Scratchpad RAM. This can be accessed either by direct addressing or
by indirect addressing. There are also some Special Function Registers (SFRs), which can only be
accessed by direct addressing. Since the Scratchpad RAM is only 256 bytes, it can be used only
when data contents are small.
FFh
Indirect
Addressing
RAM
80h
7Fh
Direct &
Indirect
Addressing
00h
RAM
SFRs
Direct
Addressing
FFFFh
64K Bytes
External Data
Memory
16K Bytes On-Chip
Program Memory
AP Flash EPROM
0000h
3FFFh
4K Bytes
LD Flash EPROM
0FFFh
Memory Map
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