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參數(shù)資料
| 型號： | DS89C440-QNL |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 19/46頁 |
| 文件大小： | 0K |
| 描述： | IC MCU FLASH 32KB 33MHZ 44-PLCC |
| 標(biāo)準(zhǔn)包裝： | 26 |
| 系列： | 89C |
| 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(shè)備： | 電源故障復(fù)位，WDT |
| 輸入/輸出數(shù)： | 32 |
| 程序存儲器容量： | 32KB（32K x 8） |
| 程序存儲器類型： | 閃存 |
| 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： | -40°C ~ 85°C |
| 封裝/外殼： | 44-LCC（J 形引線） |
| 包裝： | 管件 |
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DS89C430/DS89C450 Ultra-High-Speed Flash Microcontrollers
26 of 46
External Memory
The DS89C430 executes external memory cycles for code fetches and read/writes of external program and data
memory. A nonpage external memory cycle is four times slower than the internal memory cycles (i.e., an external
memory cycle contains four system clocks). However, a page mode external memory cycle can be completed in
one, two, or four system clocks for a page hit and two, four, or eight system clocks for a page miss, depending on
user selection. The DS89C430 also supports a second page mode operation with a different external bus structure
that provides for fast external code fetches but uses four system clock cycles for data memory access.
External Program Memory Interface (Nonpage Mode)
Figure 7 shows the timing relationship for internal and external code fetches when CD1 and CD0 are set to 10b,
assuming the microcontroller is in nonpage mode for external fetches. Note that an external program fetch takes
four system clocks, and an internal program fetch requires only one system clock.
As illustrated in Figure 7, ALE is deasserted when executing an internal memory fetch. The DS89C430 provides a
programmable user option to turn on ALE during internal program memory operation. ALE is automatically enabled
for code fetch externally, independent of the setting of this option.
PSEN
is only asserted for external code fetches, and is inactive during internal execution.
Figure 7. External Program Memory Access (Nonpage Mode, CD1:CD0 = 10)
Internal Memory Cycles
C2
C3 C4
C1
C2
C3
C4
XTAL1
ALE
Port 0
Port 2
PSEN
C1
External Memory Cycle
MSB Add
LSB Add
Data
LSB Add
Data
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS89C440-QNG | IC MCU FLASH 32KB 25MHZ 44-PLCC |
| DS89C440-MNL | IC MCU FLASH 32KB 33MHZ 40-DIP |
| DS89C440-MNG | IC MCU FLASH 32KB 25MHZ 40-DIP |
| DS89C440-ENL | IC MCU FLASH 32KB 33MHZ 44-TQFP |
| DS89C440-ENG | IC MCU FLASH 32KB 25MHZ 44-TQFP |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS89C440-QNL+ | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Ultra-High-Speed Flash Microcontrollers |
| DS89C440-XXX | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Ultra-High-Speed Flash Microcontrollers |
| DS89C450 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Ultra-High-Speed Flash Microcontrollers |
| DS89C450+ENG | 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC 64KB FLASH 5V 44TQFP - Trays |
| DS89C450+ENL | 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC 64KB FLASH 5V 44TQFP - Trays |
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