w83977atf Winbond Electronics Corp America, w83977atf Datasheet - Page 73

• Manufacturer Part Number: w83977atf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

Bit 1:
Bit 0:
Interrupt Status Register (Read Only)
Legacy IR:
This register reflects the Legacy IR interrupt status, which is encoded by different interrupt sources
into 3 bits.
Bit 7, 6: These two bits are set to a logical 1 when UFR bit 0 = 1.
Bit 5, 4: These two bits are always logical 0.
Bit 3: When not in FIFO mode, this bit is always 0. In FIFO mode, both bit 3 and 2 are set to logical
Bit 2, 1: These bits identify the priority level of the pending interrupt, as shown in the table below.
Bit 0: This bit is a logical 1 if there is no interrupt pending. If one of the interrupt sources has
TABLE: INTERRUPT CONTROL FUNCTION
** Bit 3 of ISR is enabled when bit 0 of UFR is a logical 1.
Advanced IR:
4.2.3 Set0.Reg2 - Interrupt Status Register/IR FIFO Control Register (ISR/UFR)
Legacy IR FIFO Enable FIFO Enable
Advanced
Reset Value
Bit
3
0
0
0
1
0
Mode
IR
1 when a time-out interrupt is pending.
occurred, this bit will be set to logical 0.
Bit
2
0
1
1
1
0
ISR
Bit
1
0
1
0
0
1
ETBREI - Enable TBR (Transmitter Buffer Register) Empty Interrupt
A write to 1 will enable the transmitter buffer register empty interrupt.
ERBRI - Enable RBR (Receiver Buffer Register) Interrupt
A write to 1 will enable receiver buffer register interrupt.
Bit
TMR_I
0
1
0
0
0
0
B7
0
Interrupt
priority
First
Second
Second
Third
-
Interrupt Type
IR Receive Status
RBR Data Ready
FIFO Data Time-out
TBR Empty
FSF_I
B6
0
-
INTERRUPT SET AND FUNCTION
TXTH_I DMA_I HS_I
B5
0
1
Interrupt Source
No Interrupt pending
1. OER = 1
3. NSER = 1 4. SBD = 1
1. RBR data ready
2. FIFO interrupt active level
Data present in RX FIFO for 4
characters period of time since last
access of RX FIFO.
TBR empty
- 54 -
reached
B4
0
0
2. PBER =1
IID2
B3
0
Publication Release Date:April 1998
FEND_I
USR_I/
IID1
B2
0
W83977ATF
Clear Interrupt
Read USR
1. Read RBR
2. Read RBR until FIFO
data under active level
Read RBR
1. Write data into TBR
2. Read ISR (if priority is
TXEMP_I RXTH_I
PRELIMINARY
third)
IID0
B1
1
Revision 0.52
-
B0
IP
0