XR16V794 Datasheet, PDF (26/53 Pages) Exar Corporation – HIGH PERFORMANCE 2.25V TO 3.6V QUAD UART WITH FRACTIONAL

XR16V794
HIGH PERFORMANCE 2.25V TO 3.6V QUAD UART WITH FRACTIONAL BAUD RATE
REV. 1.0.0
3.2 UART CHANNEL CONFIGURATION REGISTERS
The first 8 registers are 16550 compatible with EXAR enhanced feature registers located on the upper 8
addresses. The 4 sets of UART configuration registers are decoded using address lines A0 to A3 as shown
below.
TABLE 11: UART CHANNEL CONFIGURATION REGISTERS.
ADDRESS
REGISTER
READ/WRITE
COMMENTS
A3 A2 A1 A0
16550 COMPATIBLE
0 0 0 0 RHR - Receive Holding Reg
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 Part
Read/Write
LCR[7] = 1
0 0 0 1 IER - Interrupt Enable Reg
Read/Write
LCR[7] = 0
0 0 1 0 ISR - Interrupt Status Reg
FCR - FIFO Control Reg
Read-only
Write-only
LCR[7] = 0
0 0 1 1 LCR - Line Control Reg
Read/Write
0 1 0 0 MCR - Modem Control Reg
Read/Write
0 1 0 1 LSR - Line Status Reg
reserved
Read-only
Write-only
0 1 1 0 MSR - Modem Status Reg
- Auto RS485 Delay
Read-only
Write-only
0 1 1 1 SPR - Scratch Pad Reg
Read/Write
ENHANCED REGISTER
1 0 0 0 FCTR
Read/Write
1 0 0 1 EFR - Enhanced Function Reg
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
reserved
Write-only
Read-only
1 1 1 0 Xon-1 - Xon Character 1
reserved
Write-only
Read-only
1 1 1 1 Xon-2 - Xon Character 2
reserved
Write-only
Read-only
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