AT89LP428-20MU ATMEL [ATMEL Corporation], AT89LP428-20MU Datasheet - Page 125

• Manufacturer Part Number: AT89LP428-20MU
• Description: 8-bit Microcontroller with 4K/8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

23.9.5
3654A–MICRO–8/09
Serial Peripheral Interface
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. For In-System Programming, bytes are transferred MSB first as
shown in
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
Figure 23-9. ISP Byte Sequence
Figure 23-10. Serial Programming Interface Timing
MISO
MOSI
SCK
SS
Figure
MOSI
MISO
SCK
23-9. The SCK phase and polarity follow SPI clock mode 0 (CPOL = 0, CPHA =
t
SSE
t
SOE
7
7
t
SHSL
6
6
t
SCK
Data Sampled
Figure
t
5
5
t
SLSH
SR
23-10.
t
SOV
4
4
t
SOH
3
3
t
AT89LP428/828
SF
2
2
t
SIS
1
1
t
SIH
t
SSD
0
0
t
SOX
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