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CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
6. Operation of CSIO
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
225
Figure 6-19 Synchronous Transmission Operation (STMCR="10", TBYTE0="2")
10
0
1
・・・
9
10
1
0
STMR
STMCR
TINT
Timer
activation
activation
1
st
Byte
・・・ 10
1
0
2
nd
Byte
・・・ 10
1
0
TDRE
Transmission
data
data
Output transmission data when there is a
match between STMR and STMCR
match between STMR and STMCR
No data transmission because there is
no data (TDRE=0)
no data (TDRE=0)
2
3
4
3
rd
Byte
L
TDR RW
TBI
2
4
th
Byte
Output transmission data when there is a
match between STMR and STMCR
match between STMR and STMCR
Transmissions
counter*A
counter*A
2
1
0
2
1
0
2
TBYTE0
2
Load
Load
*A:Internal counter to be count transmission bytes
If the synchronous transmission is enabled (SACSR:TSYNE="1") and the serial timer register (STMR)
matches the serial timer comparison register (STMCR), the transmission will not start under the following
conditions.
⋅
When transmission is disabled (SCR:TXE="0")
⋅
In slave mode (SCR:MS="1")
⋅
When the chip select error (SACSR:CSE="1") occurred
⋅
When there is no valid data in the transmission data register (SSR:TDRE="1")
However, if the transmission data register contains no valid data (SSR:TDRE=1), the synchronous
transmission is enabled (SACSR:TSYNE="1"), and the serial timer register (STMR) matches the serial
timer comparison register (STMCR), writing the transmission data to transmission data register starts a
transmission immediately.
If the transmission data register (TDR) has valid transmission data (SSR:TDRE="0") after the data
transmission is completed as many as the number of data set to TBYTE, then, the transmission data will not
be sent until the serial timer register (STMR) matches the serial timer comparison register (STMCR).
However, if the synchronous transmission is enabled (SACSR:TSYNE="1") and the serial timer register
(STMR) matches the serial timer comparison register (STMCR) under the following conditions, the
transmission will not be stopped and the next transmission will be started after sending as much data as
TBYTE0.
⋅
Transmission operation in progress (SSR:TBI="0")
If synchronous reception operation is performed, disable serial data output (SMR:SOE="0"), enable
transmission operation (SCR:TXE="1"), enable reception operation (SCR:RXE="1"), and write dummy
data to TDR as many as the number of receptions.
MB91520 Series
MN705-00010-1v0-E
1538