XR16L784_08 Datasheet, PDF (25/51 Pages) Exar Corporation – HIGH PERFORMANCE 2.97V TO 5.5V QUAD UART

XR16L784
REV. 1.2.3
HIGH PERFORMANCE 2.97V TO 5.5V QUAD UART
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 REGISTERS
0 0 0 0 RHR - Receive Holding Register
Read-only
LCR[7] = 0
0 0 0 0 THR - Transmit Holding Register
Write-only
LCR[7] = 0
0 0 0 0 DLL - Div Latch Low
Read/Write
LCR[7] = 1
0 0 0 1 DLM - Div Latch High
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
Read-only
0 0 1 0 FCR - FIFO Control Register
Write-only
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
Read-only
0 1 1 0 RS485 Turn-Around Delay Register
Write-only
0 1 1 1 SPR - Scratch Pad Register
Read/Write
ENHANCED REGISTERS
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
Read-only
1 0 1 0 TXTRG - Transmit FIFO Trigger Level
Write-only
1 0 1 1 RXCNT - Receive FIFO Level Counter
Read-only
1 0 1 1 RXTRG - Receive FIFO Trigger Level
Write-only
1 1 0 0 Xoff-1 - Xoff Character 1
Write-only
1 1 0 0 Xchar
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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