XR17V354IB-E4-EVB Datasheet, PDF (41/67 Pages) Exar Corporation – HIGH PERFORMANCE QUAD PCI-EXPRESS UART

XR17V354
REV. 1.0.4
HIGH PERFORMANCE QUAD PCI-EXPRESS UART
3.5 UART CHANNEL CONFIGURATION REGISTERS
Address lines A0 to A3 select the 16 registers in each channel. The first 8 registers are 16550 compatible with
EXAR enhanced feature registers located on the upper 8 addresses.
TABLE 13: UART CHANNEL CONFIGURATION REGISTERS
ADDRESS
REGISTER
READ/WRITE
COMMENTS
A3 A2 A1 A0
16550 COMPATIBLE
0 0 0 0 RHR - Receive Holding Register
THR - Transmit Holding Register
Read-only
Write-only
LCR[7] = 0
0 0 0 0 DLL - Divisor LSB
Read/Write
LCR[7] = 1
0 0 0 1 DLM - Divisor MSB
Read/Write
LCR[7] = 1
0 0 1 0 DLD - Divisor Fractional
Read/Write
LCR[7] = 1
0 0 0 1 IER - Interrupt Enable Register
Read/Write
LCR[7] = 0
0 0 1 0 ISR - Interrupt Status Register
FCR - FIFO Control Register
Read-only
Write-only
LCR[7] = 0
0 0 1 1 LCR - Line Control Register
Read/Write
0 1 0 0 MCR - Modem Control Register
Read/Write
0 1 0 1 LSR - Line Status Register
Read-only
0 1 1 0 MSR - Modem Status Register
- Auto RS485 Delay
Read-only
Write-only
EFR bit-4 = 1
0 1 1 1 SPR - Scratch Pad Register
Read/Write
ENHANCED REGISTER
1 0 0 0 FCTR - Feature Control Register
Read/Write
1 0 0 1 EFR - Enhanced Function Register
Read/Write
1 0 1 0 TXCNT - Transmit FIFO Level Counter
TXTRG - Transmit FIFO Trigger Level
Read-only
Write-only
1 0 1 1 RXCNT - Receive FIFO Level Counter
RXTRG - Receive FIFO Trigger Level
Read-only
Write-only
1 1 0 0 Xoff-1 - Xoff Character 1
Xchar
Write-only
Read-only
Xon,Xoff Rcvd.
Flags
1 1 0 1 Xoff-2 - Xoff Character 2
Write-only
1 1 1 0 Xon-1 - Xon Character 1
Write-only
1 1 1 1 Xon-2 - Xon Character 2
Write-only
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