![](http://datasheet.mmic.net.cn/30000/M38507F8FP_datasheet_2360437/M38507F8FP_244.png)
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APPENDIX
3850 Group (Spec. H) User’s Manual
3.3 Notes on use
(3)
Setting serial I/O1 control register again (Serial I/O1)
Set the serial I/O1 control register again after the transmission and the reception circuits are reset
by clearing both the transmit enable bit and the receive enable bit to “0”.
Fig. 3.3.3 Sequence of setting serial I/O1 control register again
Clear both the transmit enable bit (TE)
and the receive enable bit (RE) to “0”
↓
Set the bits 0 to 3 and bit 6 of the
serial I/O1 control register
↓
Set both the transmit enable bit (TE) and
the receive enable bit (RE), or one of
them to “1”
Can be set with the LDM instruction at the same time
(4)
Data transmission control with referring to transmit shift register completion flag (Serial I/O1)
The transmit shift register completion flag changes from “1” to “0” with a delay of 0.5 to 1.5 shift
clocks. When data transmission is controlled with referring to the flag after writing the data to the
transmit buffer register, note the delay.
(5)
Transmit interrupt request when transmit enable bit is set (Serial I/O1)
When the transmit interrupt is used, set the transmit interrupt enable bit to transmit enabled as shown
in the following sequence.
Set the interrupt enable bit to “0” (disabled) with CLB instruction.
Prepare serial I/O for transmission/reception.
Set the interrupt request bit to “0” with CLB instruction after 1 or more instruction has been
executed.
Set the interrupt enable bit to “1” (enabled).
q Reason
When the transmission enable bit is set to “1”, the transmit buffer empty flag and transmit shift
register completion flag are set to “1”. The interrupt request is generated and the transmission
interrupt request bit is set regardless of which of the two timings listed below is selected as the timing
for the transmission interrupt to be generated.
Transmit buffer empty flag is set to “1”
Transmit shift register completion flag is set to “1”
(6)
Transmission control when external clock is selected (Serial I/O1 clock synchronous mode)
When an external clock is used as the synchronous clock for data transmission, set the transmit
enable bit to “1” at “H” of the SCLK1 input level. Also, write the transmit data to the transmit buffer
register (serial I/O shift register) at “H” of the SCLK1 input level.
(7)
Transmit data writing (Serial I/O2)
In the clock synchronous serial I/O, when selecting an external clock as synchronous clock, write the
transmit data to the serial I/O2 register (serial I/O shift register) at “H” of the transfer clock input level.