Transfer Bit Direction; Transmit Mode - Philips CEM2100/00 Service Manual

14. Synchronous Serial Interface (SIO1)
14.3 Function

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")
SIOCR<SIOS>
pin
SCK1
SIO1TDB
SO1 pin
SIO1CR<SIOS>
pin
SCK1
SIO1TDB
SO1 pin

14.3.2.1 Transmit mode

14.3.2.2 Receive mode
A
Shift out
A7
A
Shift out
A0
Figure 14-5 Transfer Bit Direction (Example of 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).
(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).
A6 A5 A4
(a) MSB transfer
A1 A2 A3
(b) LSB transfer
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T5CL8
A3 A2 A1
A4 A5 A6
A0
A7