Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
5. Operation of UART
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
140
5.1.1.
List of Interrupt of UART
The following table indicates how UART interrupt control bits relate to interrupt factors.
Table 5-1 Interrupt Control Bits and the Interrupt Factors of UART
Interrupt
type
Interrupt
request
flag bit
Flag
register
Operation
mode Interrupt factor Interrupt factor
enable bit
Interrupt request flag clear
0 1
Recep-
tion
RDRF
SSR
1-byte reception
SCR:RIE
Reading of receive data (RDR)
Reception of as
much data as
specified by
FBYTE
Reading of receive data (RDR) until
the reception FIFO is emptied
Detection of
reception idle for
8-bit time or more
while there is
valid data in the
reception FIFO
with the FRIIE bit
set to "1".
ORE
SSR
Overrun error
Writing of "1" to the reception error
flag clear bit (SSR:REC)
FRE
SSR
Framing error
PE
SSR
-
Parity error
Trans-
mission
TDRE
SSR
Transmission
register is empty
SCR:TIE
Writing to the transmit data (TDR) or
writing of "1" to the transmission FIFO
operation enable bit while the
transmission FIFO operation enable bit is
"0" and there is valid data in the
transmission FIFO (retransmission)*
writing of "1" to the transmission FIFO
operation enable bit while the
transmission FIFO operation enable bit is
"0" and there is valid data in the
transmission FIFO (retransmission)*
1
TBI
SSR
No transmission
operation
SCR:TBIE
Writing the transmit data (TDR) or
writing of "1" to the transmission FIFO
operation enable bit while the
transmission FIFO operation enable bit is
"0" and there is valid data in the
transmission FIFO (retransmission)*
writing of "1" to the transmission FIFO
operation enable bit while the
transmission FIFO operation enable bit is
"0" and there is valid data in the
transmission FIFO (retransmission)*
1
FDRQ
FCR1
The storage data
value of the
transmission FIFO
is FTICR setting
value or less, or
empty
FCR1:FTIE
Writing of "0" to the FIFO transmission
data request bit (FCR1:FDRQ) or the
transmission FIFO is full
data request bit (FCR1:FDRQ) or the
transmission FIFO is full
Status
TINT
SACSR
Serial Timer
Register (STMR)
matched Serial
Timer Comparison
Register
(STMCR)
SACSR:TINTE
Writing "0" to the timer interrupt flag bit
(SACSR:TINT)
(SACSR:TINT)
*1: Set the TIE bit to "1" after the TDRE bit is cleared to "0".
: Operation mode effective
-: Operation mode non-effective
MB91520 Series
MN705-00010-1v0-E
1453