259
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Interrupt Function
The serial I/O is set by the transfer end flag (SIF) bit when data transfer ends. In this case, the interrupt
request is generated. When termination (suspension) is executed by inputting chip select, the chip select
termination flag (CSAF) bit is set and an interrupt request is generated.
Figure 17.4-6 Interrupt generation timing
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Start/Stop Timing of Shift Operation
Writing "1" to the ST bit of the SCR initiates transfer, whereas writing "0" stops transfer. (When XCS input
is enabled, transfer does not start until the falling of the XCS pin is detected after writing "1" to the ST bit.)
When data transfer ends, clears the ST bit automatically to "0" and stops operation.
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Internal shift clock mode
Figure 17.4-7 Shift operation start/stop timing
Internal Clock Mode 1 byte Transmission
Transfer End Interruption
#0 #1 #2 #3 #4 #5 #6 #7
#0 #1 #2 #3 #4 #5 #6 #7
#0 #1 #2 #3 #4
INT-REQ
CSAF
XCS
SO
SCK
(INT-REQ)SIF
SO
SCK
STB
SO
SCK
(INT-REQ)SIF
External Clock Mode 1 byte Transmission
Transfer End Interruption
Internal Clock Mode 1 byte Transmission
Forced End Interruption of XCS
At 1 byte Transmission end
#0 #1 #2 #3 #4 #5 #6 #7
#0 #1 #2 #3 #4 #5
ST
SIF
SO
SCK
SIF
SO
SCK
ST
At 1 byte Transmission suspend