W83977ATF Datasheet, PDF (73/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
Bit 1:
Bit 0:
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.
4.2.3 Set0.Reg2 - Interrupt Status Register/IR FIFO Control Register (ISR/UFR)
Interrupt Status Register (Read Only)
Mode
B7
B6
B5
B4 B3
Legacy IR FIFO Enable FIFO Enable 0
0 IID2
Advanced
IR
TMR_I
FSF_I TXTH_I DMA_I HS_I
Reset Value
0
0
1
0
0
B2
IID1
USR_I/
FEND_I
0
B1
B0
IID0
IP
TXEMP_I RXTH_I
1
0
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
1 when a time-out interrupt is pending.
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
occurred, this bit will be set to logical 0.
TABLE: INTERRUPT CONTROL FUNCTION
ISR
INTERRUPT SET AND FUNCTION
Bit Bit Bit Bit Interrupt Interrupt Type
3 2 1 0 priority
Interrupt Source
Clear Interrupt
0 001
-
-
No Interrupt pending
-
0 1 1 0 First
IR Receive Status
1. OER = 1 2. PBER =1
Read USR
3. NSER = 1 4. SBD = 1
0 1 0 0 Second RBR Data Ready
1. RBR data ready
1. Read RBR
2. FIFO interrupt active level
reached
2. Read RBR until FIFO
data under active level
1 1 0 0 Second FIFO Data Time-out Data present in RX FIFO for 4
Read RBR
characters period of time since last
access of RX FIFO.
0 0 1 0 Third
TBR Empty
TBR empty
1. Write data into TBR
2. Read ISR (if priority is
third)
** Bit 3 of ISR is enabled when bit 0 of UFR is a logical 1.
Advanced IR:
- 54 -
Publication Release Date:April 1998
Revision 0.52