Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
6. Operation of CSIO
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
226
Notes:
⋅
If the synchronous transmission is enabled (SACSR:TSYNE="1"), the external trigger is enabled
(SACSR:TRGE="1"), and the serial timer comparison register (STMCR) is set to (0000)H, it will not
operate the synchronous transmission but the transmission by external trigger.
⋅
When the transmit data register (TDR) has no valid transmission data (SSR:TDRE="1") before sending
the data frame of TBYTE setting, the following operation will be performed.
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When the transfer byte error is enabled (TBEEN="1"), a chip select error (SACSR:CSE="1") occurs.
When the chip select error flag (SACSR:CSE) is set to "1", writing the transmission data to the
transmission data register (TDR) does not start transmission operation.
⋅
When the transfer byte error is disabled (TBEEN="0"), transmission operation will be stopped until
transmission data is written to the transmission data register (TDR). Transmission operation will be
restarted when transmission data is written to the transmission data register (TDR).
Transmission Operation by External Trigger
If the synchronous transmission is enabled (SACSR:TSYNE="1"), the external trigger is enabled
(SACSR:TRGE="1"), the timer comparison register (STMCR) is set to (0000)H, the transmission is
enabled (SCR:TXE="1"), and the valid data exists (SSR:TDRE="0"), the transmission operation by the
external trigger starts.
Starting the transmission operation by the external trigger operates as shown below:
1. If the edge of the external trigger which is set with the trigger selection bit (SACSR:TRG1, 0) is
detected, the transmission operation starts immediately. It continues to send the same number of data as
the number set to TBYTE.
2. If the data transmission is completed as many as the number of data set to TBYTE0, then, the
transmission operation stops until the edge of the external trigger which is set with the trigger selection
bit (SACSR:TRG1, 0) is detected.
MB91520 Series
MN705-00010-1v0-E
1539