XR16L2450 Datasheet, PDF (12/30 Pages) Exar Corporation – 2.25V TO 5.5V DUART

XR16L2450
2.25V TO 5.5V DUART
xr
REV. 1.1.0
3.0 UART INTERNAL REGISTERS
Each of the UART channel in the L2450 has its own set of configuration registers selected by address lines A0,
A1 and A2 with CSA# or CSB# selecting the channel. The registers are 16C450 compatible. The complete
register set is shown on Table 4 and Table 5.
TABLE 4: 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
DLL - Div Latch Low Byte
Read/Write
LCR[7] = 1
0 01
DLM - Div Latch High Byte
Read/Write
0 00
0 01
DREV - Device Revision
DVID - Device ID
Read/Write
Read/Write
LCR[7] = 1,
DLL = 0x00, DLM = 0x00
0 01
IER - Interrupt Enable Register
Read/Write
LCR[7] = 0
0 10
ISR - Interrupt Status Register
Reserved
Read-only
Write-only
0 11
LCR - Line Control Register
Read/Write
1 00
MCR - Modem Control Register
Read/Write
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
12