MCS9845 MosChip Semiconductor, MCS9845 Datasheet - Page 13

• Manufacturer Part Number: MCS9845
• Description: PCI Dual UART
• Manufacturer: MosChip Semiconductor

Rev. 2.5
UART Register Table
DLL and DLM are accessible only when LCR Bit-7=1.
U1: Internal UART-A chip select
U2: Internal UART-B chip select (if two UARTs are present)
Master Reset Conditions
CS
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
Un
A2
0
0
0
0
0
0
1
1
1
1
0
0
A1
0
0
0
1
1
1
0
0
1
1
0
0
A0
0
1
0
0
1
0
0
1
0
1
0
1
Register
MCR
RHR
MSR
DLM
THR
FCR
LCR
LSR
SPR
DLL
IER
IIR
Register
MCR
RHR
MSR
THR
FCR
LCR
LSR
SPR
IER
IIR
Enabled
Trigger
Enable
Divisor
RCVR
(MSB)
Bit-15
Latch
Bit-7
FIFO
FIFO
Error
Bit-7
Bit-7
Bit-7
Bit-7
nCD
Bit-7
0/
0/
0
0
X
X
0
0
0
0
0
0
0
0
Bit-6
Enabled
Trigger
X
X
RCVR
Empty
0
0
0
0
0
0
1
0
(LSB)
Break
Bit-14
XMIT
Bit-6
FIFO
Bit-6
Bit-6
Bit-6
Bit-6
Set
nRI
0/
0
0
Bit-5
X
X
0
0
0
0
0
0
1
0
Hardware
Holding
Control
Empty
nDSR
Parity
Bit-13
XMIT
Bit-5
Bit-5
Bit-5
Flow
Bit-5
Bit-5
Set
Bit-4
0
0
0
X
X
0
0
0
0
0
0
0
0
Bit-3
Interrupt
0
X
0
0
0
0
0
0
0
0
Parity
Break
nCTS
Bit-12
Bit-4
Even
Loop
Back
Bit-4
Bit-4
Bit-4
Bit-4
PCI Dual UART with ISA Bridge
0
0
0
Bit-2
X
0
0
0
0
0
0
0
0
0
Interrupt
Interrupt
Interrupt
Framing
Modem
Priority
Enable
Enable
(nOP2)
Status
(Bit-2)
Parity
Bit-11
Bit-3
Error
Delta
Bit-3
Bit-3
Bit-3
Bit-3
nCD
Bit-1
0
X
0
0
0
0
0
0
0
0
0
MCS9845
Bit-0
Interrupt
Interrupt
Receive
Priority
(nOP1)
0
X
0
0
1
0
0
0
0
0
Status
(Bit-1)
Reset
Parity
Bit-10
XMIT
Delta
Bit-2
FIFO
Error
Bit-2
Bit-2
Stop
Bit-2
Bit-2
Line
Bits
nRI
Transmit
Register
Interrupt
Overrun
Holding
Priority
Length
RCVR
(Bit-0)
(Bit-1)
nDSR
Reset
nRTS
Word
Bit-1
FIFO
Error
Delta
Bit-1
Bit-1
Bit-1
Bit-1
Bit-9
w w w . D a t a S h e e t 4 U . c o m
Register
Interrupt
Receive
Receive
Holding
Enable
Length
Page 13
Status
Ready
(Bit-0)
nDTR
nCTS
Word
Bit-0
FIFO
Delta
Bit-0
Bit-0
Data
Bit-0
Bit-0
Bit-8