Operation In Synchronous Mode (Operation Mode 2) - Fujitsu MB90335 Series Hardware Manual

MB90335 Series
18.7.2

Operation in Synchronous Mode (Operation Mode 2)

The UART uses clock-synchronous transfer when used in operation mode 2 (normal
mode).
■ Operation in Synchronous Mode (Operation Mode 2)
●
Format of transmit/receive data
In the synchronous mode, 1 to 8 bits of data is transferred and the stop bit is not appended. Figure 18.7-3
shows the formats of send and receive data in the clock synchronization mode.
Figure 18.7-3 Format of Transmit/Receive Data (Operation Mode 2)
When transfer by output serial clock (7 bits of data length and LSB first)
Transfer data write
When transfer by input serial clock (7 bits of data length and LSB first)
Receive data write
●
Clock Supply
In the clock synchronous mode, count of clocks equal to the transmit and receive bits count must be
supplied.
When the internal clock (a dedicated baud rate generator) has been selected, the synchronous clock for
receiving data is automatically generated by sending data.
When the external clock has been selected, exactly one byte of clock should be provided externally after
making sure that the serial output data registers 0, 1 (SODR0, SODR1) contains sending data (SSR0, SSR1:
TDRE=0). Also, both before and after sending, ensure that the level is marked with "H".
CM44-10137-6E
SCK0, SCK1 output
SOT0, SOT1
(LSB)
1
TXE
SCK0, SCK1 output
SIN0, SIN1
(LSB) 1
RXE
FUJITSU MICROELECTRONICS LIMITED
18.7 Explanation of Operation of UART
0 1 1 0 0
Transfer data
0 1 1 0 0
Receive data
CHAPTER 18 UART
Mark level
(MSB)
1
Mark level
(MSB)
1
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