DS89C420-MNL Maxim Integrated Products, DS89C420-MNL Datasheet - Page 33

• Manufacturer Part Number: DS89C420-MNL
• Description: IC MCU ULTRA 33MHZ HP 40-DIP
• Manufacturer: Maxim Integrated Products
• Series: 89Cr

Specifications of DS89C420-MNL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 33MHz
• Connectivity: EBI/EMI, SIO, UART/USART
• Peripherals: Power-Fail Reset, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

Figure 13. Page Mode 1, External Data Memory Access (Pages = 01, Stretch = 1, CD = 10)
Figure 13
PAGES1:PAGES0 = 01. The stretch cycle shown is for a stretch value of 1 and is coincident with a page miss.
Note that the first stretch value does not result in adding four system clocks to the RD/WR control signals. This is
because the first stretch uses one system clock to create additional setup and one system clock to create
additional hold time.
RD / WR
RD / WR
RD / WR
XTAL1
PSEN
Port 0
Port 2
PSEN
Port 0
Port 2
PSEN
Port 0
Port 2
ALE
ALE
ALE
illustrates the external data-memory stretch cycle timing relationship when PAGEE = 1 and
LSB Addr
LSB Addr
LSB Addr
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MOVX Inst
Fetch
MOVX Inst
Fetch
LSB Addr
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LSB Addr
MOVX
MOVX
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LSB Addr
MSB Addr
MSB Addr
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MSB Addr
LSB Addr
LSB Addr
Memory Access (Stretch =1)
MOVX
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MOVX Instruction
MOVX Instruction
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Memory Access (Stretch =1)
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Memory Access (Stretch =1)
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LSB Addr
MOVX Instruction
Data
Data
LSB Addr
Data
LSB Addr
LSB Addr
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LSB Addr
LSB Addr
LSB Addr
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LSB Addr
LSB Addr
LSB Addr
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