EM78P809N
8-Bit Microcontroller
shiftstart
shiftstart
SPIS
shiftfinish
shiftfinish
RBF
W BE
/SCK pin
SO pin
SIpin
b0 b1 b2 b3 b4 b5 b6 b7
d0 d1 d2 d3 d4 d5 d6 d7
a0 a1 a2 a3 a4 a5 a6 a7
c0 c1 c2 c3 c4 c5 c6 c7
SPIF
SPID
a
c
b
d
writedata
readdata writedata
readdata
Fig. 17. Transmit/Receive Mode (8-bit, 1 word)
(d) Multiple Device Connect (/SS):
When selecting external clock for transfer clock source, the /SS function can be
used. This pin (/SS) will be active when the /SS function is enabled, else the /SS
pin is a general purpose I/O. Ignore the data on the SDI and SDO pins while /SS
is high, since the SDO is no longer driven.
SDO
SDI
SCK
/SS
PP.6677
Master
P66
P 65
P65
PP6644
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
Slave Device 1
Slave Device 2
Slave Device 3
Slave Device 4
Fig. 18. The SPI Configuration Example of Single-Master and Multi-Slaves
Product Specification (V1.0) 07.26.2005
• 39
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
