AT89LP51 Atmel Corporation, AT89LP51 Datasheet - Page 89

• 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

17.9.4
17.9.5
3709D–MICRO–12/11
ISP Exit Sequence
Serial Peripheral Interface
Figure 17-11. In-System Programming (ISP) Start Sequence
Execute this sequence to exit ISP mode and resume CPU execution mode.
Figure 17-12. In-System Programming (ISP) Exit Sequence
Note:
The Serial Peripheral Interface (SPI) is a byte-oriented full-duplex synchronous serial communi-
cation channel. During In-System Programming, the programmer always acts as the SPI master
and the target device always acts as the SPI slave. The target device receives serial data on
MOSI and outputs serial data on MISO. The Programming Interface implements a standard
SPI Port with a fixed data order and For In-System Programming, bytes are transferred MSB
first as shown in
CPHA = 0) where bits are sampled on the rising edge of SCK and output on the falling edge of
SCK. For more detailed timing information see
1. Drive SCK low.
1. Wait at least t
2. Tristate MOSI.
3. Wait at least t
4. Wait t
The waveforms on this page are not to scale.
XTAL1
XTAL1
MISO
MOSI
MISO
MOSI
RST
SCK
RST
SCK
V
V
SSZ
DD
DD
and tristate SCK.
Figure
SSD
RHZ
.
t
SSD
and bring RST low.
17-13. The SCK phase and polarity follow SPI clock mode 0 (CPOL = 0,
t
RHZ
t
SSZ
t
Figure
RLZ
HIGH Z
HIGH Z
17-14.
t
STL
HIGH Z
HIGH Z
t
ZSS
AT89LP51/52
t
SSE
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