參數(shù)資料
型號(hào)： 89C538
廠商： NXP Semiconductors N.V.
英文描述： CMOS single-chip 8-bit microcontrollers with FLASH program memory
中文描述： CMOS單芯片8位微控制器的FLASH程序存儲(chǔ)器
文件頁(yè)數(shù)： 15/35頁(yè)
文件大?。?/td> 221K
代理商： 89C538
Philips Semiconductors
Preliminary specification
89C535/89C536/89C538
CMOS single-chip 8-bit microcontrollers
with FLASH program memory
1997 Jun 05
15
Expanded Data RAM Addressing
The 89C535/536/538 has internal data memory that is mapped into
four separate segments: the lower 128 bytes of RAM, upper 128
bytes of RAM, 128 bytes Special Function Register (SFR), and 256
bytes expanded RAM (ERAM).
The four segments are:
1. The Lower 128 bytes of RAM (addresses 00H to 7FH) are
directly and indirectly addressable.
2. The Upper 128 bytes of RAM (addresses 80H to FFH) are
indirectly addressable only.
3. The Special Function Registers, SFRs, (addresses 80H to FFH)
are directly addressable only.
4. The 256-bytes expanded RAM (ERAM, 00H – FFH) are indirectly
accessed by move external instruction, MOVX.
The Lower 128 bytes can be accessed by either direct or indirect
addressing. The Upper 128 bytes can be accessed by indirect
addressing only. The Upper 128 bytes occupy the same address
space as the SFRs. That means they have the same address, but
are physically separate from SFR space.
When an instruction accesses an internal location above address
7FH, the CPU knows whether the access is to the upper 128 bytes
of data RAM or to SFR space by the addressing mode used in the
instruction. Instructions that use direct addressing access SFR
space. For example:
MOV 0A0H,#data
accesses the SFR at location 0A0H (which is P2). Instructions that
use indirect addressing access the Upper 128 bytes of data RAM.
For example:
MOV @R0,#data
where R0 contains 0A0H, accesses the data byte at address 0A0H,
rather than P2 (whose address is 0A0H).
The ERAM can be accessed by indirect addressing and MOVX
instructions. This part of memory is physically located on-chip,
logically occupies the first 256-bytes of external data memory.
The ERAM is indirectly addressed, using the MOVX instruction in
combination with any of the registers R0, R1 of the selected bank or
DPTR. An access to ERAM will not affect ports P0, P3.6 (WR#) and
P3.7 (RD#). P2 SFR is output during external addressing.
For example,
MOVX @R0,#data
where R0 contains 0A0H, accesses the ERAM at address 0A0H
rather than external memory. An access to external data memory
locations higher than FFH (i.e., 0100H to FFFFH) will be performed
with the MOVX DPTR instructions in the same way as in the
standard 80C51, so with P0 and P2 as data/address bus, and P3.6
and P3.7 as write and read timing signals. Refer to Figure 8.
External data memory cannot be accessed using the MOVX with R0
or R1. This will always access the ERAM.
The stack pointer (SP) may be located anywhere in the 256 bytes
RAM (lower and upper RAM) internal data memory. The stack may
not be located in the ERAM.
ERAM
256 BYTES
UPPER
128 BYTES
INTERNAL RAM
LOWER
128 BYTES
INTERNAL RAM
SPECIAL
FUNCTION
REGISTER
FF
00
FF
00
FF
00
80
80
EXTERNAL
DATA
MEMORY
FFFF
0000
0100
SU00868
Figure 8.
Internal and External Data Memory Address Space
相關(guān)PDF資料
PDF描述
89C535 CMOS single-chip 8-bit microcontrollers with FLASH program memory
89C54 80C51 8-bit microcontroller family 4K/8K/16K/32K Flash
89C51 80C51 8-bit microcontroller family 4K Flash(80C51八位微控制器系列 4K 閃速存儲(chǔ)器)
89C52 80C51 8-bit microcontroller family8KFlash(80C51八位微控制器系列 8K閃速存儲(chǔ)器)
89C58 80C51 8-bit microcontroller family 4K/8K/16K/32K Flash
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
89C54 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:80C51 8-bit microcontroller family 4K/8K/16K/32K Flash
89C55 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:8-Bit Microcontroller with 20K Bytes Flash
89C58 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:80C51 8-bit microcontroller family 4K/8K/16K/32K Flash
89C59 制造商:SST 制造商全稱:Silicon Storage Technology, Inc 功能描述:FlashFlex51 MCU
89C61X2 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:80C51 8-bit Flash microcontroller family
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