AT89S4051 Atmel Corporation, AT89S4051 Datasheet - Page 34

• Manufacturer Part Number: AT89S4051
• Manufacturer: Atmel Corporation

Specifications of AT89S4051

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 15
• Uart: 1
• Sram (kbytes): 0.25
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 2
• Isp: SPI

35. Power-up Sequence
36. ISP Start Sequence
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AT89S2051/S4051
Execute this sequence to power-up the device before programming.
Figure 35-1. ISP Power-up Sequence
Execute this sequence to enter ISP when the device is already operational.
Figure 36-1. ISP Start Sequence
1. Apply power between VCC and GND pins.
2. Keep SCK (P1.7) at GND.
3. Wait 10 µs and bring RST to “H”.
4. If a crystal is connected between XTAL1 and XTAL2, wait at least 10 ms; otherwise,
1. Bring SCK (P1.7) to GND.
2. Tri-state MISO (P1.6).
3. Bring RST to “H”.
P1.6/MISO
P1.5/MOSI
P1.6/MISO
P1.5/MOSI
P1.7/SCK
apply a 3 - 24 MHz clock to XTAL1 and wait 4 ms.
P1.7/SCK
XTAL1
XTAL1
RST
V
RST
V
CC
CC
High Z
High Z
3390E–MICRO–6/08