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
224
How to Stop Serial Timer
When the serial timer enable bit (SACSR:TMRE) is set to "0", the serial timer will stop. The value of the
serial timer register (STMR) is retained.
Timer Operation
When the synchronous transmission enable bit (SAGSR:TSYNE) is set to "0", the serial timer operates as a
timer.
If the serial timer register (STMR) matches the serial timer comparison register (STMCR), the timer
interrupt flag (SACSR:TINT) is set to "1" and the serial timer register (STMR) is reset to "0".
Figure 6-18 Timer Operation (STMCR="10")
10
0
1
2
・・・
9
10
1
0
STMR
STMCR
TINT
Timer activation
2
・・・
9
10
1
0
Writing “0”
to TINT
to TINT
Note:
When the timer comparison register (STMCR) is set to (0000) H with the synchronous transmission
disabled (SACSR:TSYNE=0), the timer interrupt flag (SACSR:TINT) is fixed to "1" if the timer is
operating and the division value of the timer operating clock (SACSR:TDIV) is set to "0000"b.
Synchronous Transmission Operation
When the synchronous transmission enable bit (SAGSR:TSYNE) is set to "1", the serial timer is used for a
synchronous transmission.
The synchronous transmission operates as shown below:
1. If the transmission data register contains data (SSR:TDRE="0") and the serial timer register
(STMR) matches the serial timer comparison register (STMCR), the transmission operation starts
and the serial timer register (STMR) is reset to "0". It continues to send the same number of data as
the number set to TBYTE0.
2. If the data transmission is completed as many as the number of data set to TBYTE0, then, the
transmission operation stops until the serial timer register (STMR) matches the serial timer
comparison register (STMCR).
MB91520 Series
MN705-00010-1v0-E
1537