XR16L2751 Datasheet, PDF (22/52 Pages) Exar Corporation – 2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE

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XR16L2751
2.25V TO 5.5V DUART WITH 64-BYTE FIFO AND POWERSAVE
REV. 1.0.0
3.0 UART INTERNAL REGISTERS
Each of the UART channel in the 2751 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 8 and
Table 9.
TABLE 8: 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
LCR[7] = 1, LCR ≠ 0xBF
0 00
DREV - Device Revision Code
Read-only
DLL, DLM = 0x00,
LCR[7] = 1, LCR ≠ 0xBF
0 01
DVID - Device Identification Code
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
LCR[7] = 0
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
LCR[7] = 0
1 10
MSR - Modem Status Register
Reserved
Read-only
Write-only
LCR[7] = 0
1 11
SPR - Scratchpad Register
Read/Write LCR[7] = 0, FCTR[6] = 0
1 11
FLVL - RX/TX FIFO Level Counter Register
Read-only
LCR[7] = 0, FCTR[6] = 1
1 11
EMSR - Enhanced Mode Select Register
Write-only
LCR[7] = 0, FCTR[6] = 1
ENHANCED REGISTERS
0 00
TRG - RX/TX FIFO Trigger Level Register
FC - RX/TX FIFO Level Counter Register
Write-only
Read-only
LCR = 0xBF
0 01
FCTR - Feature Control Register
Read/Write
LCR = 0xBF
0 10
EFR - Enhanced Function Register
Read/Write
LCR = 0xBF
1 00
Xon-1 - Xon Character 1
Read/Write
LCR = 0xBF
1 01
Xon-2 - Xon Character 2
Read/Write
LCR = 0xBF
1 10
Xoff-1 - Xoff Character 1
Read/Write
LCR = 0xBF
1 11
Xoff-2 - Xoff Character 2
Read/Write
LCR = 0xBF
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