參數(shù)資料
型號: DS87C520-WCL
廠商: Maxim Integrated Products
文件頁數(shù): 3/43頁
文件大小: 0K
描述: IC MCU EPROM/ROM 33MHZ HS 40CDIP
產品培訓模塊: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標準包裝: 10
系列: 87C
核心處理器: 8051
芯體尺寸: 8-位
速度: 33MHz
連通性: EBI/EMI,SIO,UART/USART
外圍設備: 電源故障復位,WDT
輸入/輸出數(shù): 32
程序存儲器容量: 16KB(16K x 8)
程序存儲器類型: EPROM,UV
RAM 容量: 1K x 8
電壓 - 電源 (Vcc/Vdd): 4.5 V ~ 5.5 V
振蕩器型: 外部
工作溫度: 0°C ~ 70°C
封裝/外殼: 40-CDIP(0.600",15.24mm)窗口
包裝: 管件
其它名稱: DS87C520WCL
DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers
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16kB internal program space. If software reconfigures the ROMSIZE register to 4kB (0000h–0FFFh) in
the current state, the device will immediately jump to external program execution because program code
from 4kB to 16kB (1000h–3FFFh) is no longer located on-chip. This could result in code misalignment
and execution of an invalid instruction. The recommended method is to modify the ROMSIZE register
from a location in memory that will be internal (or external) both before and after the operation. In the
above example, the instruction which modifies the ROMSIZE register should be located below the 4kB
(1000h) boundary, so that it will be unaffected by the memory modification. The same precaution should
be applied if the internal program memory size is modified while executing from external program
memory.
Off-chip memory is accessed using the multiplexed address/data bus on P0 and the MSB address on P2.
While serving as a memory bus, these pins are not I/O ports. This convention follows the standard 8051
method of expanding on-chip memory. Off-chip ROM access also occurs if the
EA pin is a logic 0. EA
overrides all bit settings. The
PSEN signal goes active (low) to serve as a chip enable or output enable
when Ports 0 and 2 fetch from external ROM.
Figure 2. ROM Memory Map
DATA MEMORY ACCESS
Unlike many 8051 derivatives, the DS87C520/DS83C520 contain on-chip data memory. They also
contain the standard 256 bytes of RAM accessed by direct instructions. These areas are separate. The
MOVX instruction accesses the on-chip data memory. Although physically on-chip, software treats this
area as though it was located off-chip. The 1kB of SRAM is between address 0000h and 03FFh.
Access to the on-chip data RAM is optional under software control. When enabled by software, the data
SRAM is between 0000h and 03FFh. Any MOVX instruction that uses this area will go to the on-chip
RAM while enabled. MOVX addresses greater than 03FFh automatically go to external memory through
Ports 0 and 2.
ROM SIZE IGNORED
ROM SIZE ADJUSTABLE
DEFAULT = 16kB
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