XR16C2850 Datasheet, PDF (18/43 Pages) Exar Corporation – 3.3V AND 5V DUART WITH 128-BYTE FIFO

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3.3V AND 5V DUART WITH 128-BYTE FIFO
XR16C2850
REV. 2.0.0
3.0 UART INTERNAL REGISTERS
Each of the UART channel in the 2850 has its own set
of configuration registers selected by address lines
A0, A1 and A2 with CSA# or CSB# selecting the
channel. The complete register set is shown on
Table 7 and Table 8.
TABLE 7: UART CHANNEL A AND B UART INTERNAL REGISTERS
A2,A1,A0 ADDRESSES
REGISTER
READ/WRITE
COMMENTS
16C550 COMPATIBLE REGISTERS
0 00
RHR - Receive Holding Register
THR - Transmit Holding Register
Read-only
Write-only
LCR[7] = 0
0 00
0 01
DLL - Div Latch Low Byte
DLM - Div Latch High Byte
Read/Write
Read/Write
LCR[7] = 1, LCR ≠ 0xBF
0 00
0 01
DREV - Device Revision Code
DVID - Device Identification Code
Read-only
Read-only
DLL, DLM = 0x00,
LCR[7] = 1, LCR ≠ 0xBF
0 01
IER - Interrupt Enable Register
Read/Write
LCR[7] = 0
0 10
ISR - Interrupt Status Register
FCR - FIFO Control Register
Read-only
Write-only
0 11
LCR - Line Control Register
Read/Write
1 00
MCR - Modem Control Register
Read/Write
LCR[7] = 0
1 01
LSR - Line Status Register
Reserved
Read-only
Write-only
1 10
MSR - Modem Status Register
Reserved
Read-only
Write-only
1 11
SPR - Scratch Pad Register
Read/Write
LCR[7] = 0, FCTR[6] = 0
1 11
FLVL - TX/RX FIFO Level Counter Register
Read-only
LCR[7] = 0, FCTR[6] = 1
1 11
EMSR - Enhanced Mode Select Register
Write-only
ENHANCED REGISTERS
0 00
TRG - TX/RX FIFO Trigger Level Reg
FC - TX/RX FIFO Level Counter Register
Write-only
Read-only
LCR = 0xBF
0 01
FCTR - Feature Control Reg
Read/Write
0 10
EFR - Enhanced Function Reg
Read/Write
1 00
Xon-1 - Xon Character 1
Read/Write
1 01
Xon-2 - Xon Character 2
Read/Write
1 10
Xoff-1 - Xoff Character 1
Read/Write
1 11
Xoff-2 - Xoff Character 2
Read/Write
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