Fujitsu FR81S Manual Do Utilizador
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
5. Operation of UART
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
163
Figure 5-16 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")
⋅
When there is no valid data in the transmission data register (SSR:TDRE="1")
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")
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.
⋅
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).
MB91520 Series
MN705-00010-1v0-E
1476