CHAPTER 13 SERIAL INTERFACE CHANNEL 0
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User’s Manual U11302EJ4V0UM
(d) For the pin that is to be used for data I/O, be sure to set as follows before serial transfer of the 1st
byte after RESET input.
[1] Set the P25 and P26 output latches to 1.
[2] Set bit 0 (RELT) of the serial bus interface control register (SBIC) to 1.
[3] Reset the P25 and P26 output latches from 1 to 0.
(e) If the SB0 (SB1) line changes from low level to high level or from high level to low level while the
SCK0 line is high level, it is recognized as either a bus release signal or a command signal. Therefore,
if the changing timing of the bus fluctuates because of substrate capacitance, etc., it may be
recognized as a bus release signal (or a command signal) even while data is being transmitted. Care
should therefore be taken in the wiring.
13.4.4 2-wire serial I/O mode operation
The 2-wire serial I/O mode can handle any communication format by program.
Communication is basically carried out using two lines: a serial clock (SCK0) and serial data input/output (SB0
or SB1).
Figure 13-30. Serial Bus Configuration Example Using 2-Wire Serial I/O Mode
(1) Register setting
The 2-wire serial I/O mode is set by serial operating mode register 0 (CSIM0), the serial bus interface
control register (SBIC), and the interrupt timing specification register (SINT).
Master
SCK0
Slave
SB0 (SB1)
SCK0
SB0 (SB1)
V
DD
V
DD
Содержание mPD780204
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