Rainbow Electronics AT89LP214 - Manual (Page 74)

74
3538A–MICRO–7/06
AT89LP213/214 [Preliminary]
23.8.5 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 and For In-System programming, bytes are transferred MSB first
as shown in
Figure 23-9 . The SCK phase and polarity follow SPI clock mode 0 (CPOL = 0,
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
Figure 23-10 .
Figure 23-9. ISP Byte Sequence
Figure 23-10. Serial Programming Interface Timing
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
MOSI
MISO
SCK
Data Sampled
t
SR t
SSE
t
SLSH
t
SOV
t
SF
t
SOX
t
SSD
t
SCK
t
SHSL
t
SOE
t
SOH
t
SIH
t
SIS
SS
SCK
MISO
MOSI