AT89LP51 Atmel Corporation, AT89LP51 Datasheet - Page 88

• Manufacturer Part Number: AT89LP51
• Manufacturer: Atmel Corporation

Specifications of AT89LP51

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 36
• Uart: 1
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 3
• Isp: SPI
• Watchdog: Yes

17.9.2
17.9.3
88
AT89LP51/52
Power-down Sequence
ISP Start Sequence
Figure 17-9. Serial Programming Power-up Sequence
Execute this sequence to power-down the device after programming.
Figure 17-10. Serial Programming Power-down Sequence
Execute this sequence to exit CPU execution mode and enter ISP mode when the device has
passed Power-On Reset and is already operational.
1. Drive SCK low.
2. Wait at least t
3. Wait at least t
4. Wait at least t
5. Wait no more than t
1. Drive RST high.
2. Wait t
3. Drive SCK low.
4. Start programming session.
MISO
MOSI
RST
SCK
RST
V
DD
MISO
MOSI
RST
SCK
V
RLZ
DD
+ t
STL
SSD
RHZ
SSZ
.
t
and tristate SCK.
and Tristate MOSI.
and drive RST low.
SSD
PWRDN
t
PWRUP
and power off VDD.
t
RHZ
HIGH Z
HIGH Z
t
POR
+ t
t
SSZ
SUT
HIGH Z
HIGH Z
t
PWRDN
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