Philips CEM2100/00, Service Manual

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Page 164
14. Synchronous Serial Interface (SIO1)
14.3 Function
T
5CL8
14.3.2 Transfer bit direction
Transfer data direction can be selected by using SIO1CR<SIODIR>. The transfer data direction can't be set
individually for transmit and receive operations.
When the data direction is changed, the writing instruction to SIO1CR<SIODIR> should be executed while
the transfer is stopped (when SIO1CR<SIOF>= “0”)
Figure 14-5 Transfer Bit Direction (Example of transmit mode)
14.3.2.1 Transmit mode
(1) MSB transmit mode
MSB transmit mode is selected by setting SIO1CR<SIODIR> to “0”, in which case the data is
transferred sequentially beginning with the most significant bit (Bit7).
(2) LSB transmit mode
LSB transmit mode is selected by setting SIO1CR<SIODIR> to “1”, in which case the data is
transferred sequentially beginning with the least significant bit (Bit0).
14.3.2.2 Receive mode
(1) MSB receive mode
MSB receive mode is selected by setting SIO1CR<SIODIR> to “0”, in which case the data is
received sequentially beginning with the most significant bit (Bit7).
(b) LSB transfer
A0
A
A1 A2
(a) MSB transfer
A3 A4 A5 A6 A7
Shift out
A7
A
A6 A5 A4 A3 A2 A1 A0
Shift out
SIOCR<SIOS>
SCK1
pin
SIO1TDB
SO1 pin
SIO1CR<SIOS>
SCK1
pin
SIO1TDB
SO1 pin