XR16M554 Datasheet, PDF (19/46 Pages) Exar Corporation – 1.62V TO 3.63V QUAD UART WITH 16-BYTE FIFO

XR16M554/554D
REV. 1.0.0
1.62V TO 3.63V QUAD UART WITH 16-BYTE FIFO
3.0 UART INTERNAL REGISTERS
Each UART channel in the M554 has its own set of configuration registers selected by address lines A0, A1
and A2 with a specific channel selected (See Table 1 and Table 2). The complete register set is shown on
Table 7 and Table 8.
TABLE 7: UART CHANNEL A AND B UART INTERNAL REGISTERS
A2,A1,A0 ADDRESSES
REGISTER
READ/WRITE
COMMENTS
16C550 COMPATIBLE REGISTERS
000
RHR - Receive Holding Register
THR - Transmit Holding Register
Read-only
Write-only
LCR[7] = 0
000
001
DLL - Divisor LSB
DLM - Divisor MSB
Read/Write
Read/Write
LCR[7] = 1, LCR ≠ 0xBF
001
010
IER - Interrupt Enable Register
ISR - Interrupt Status Register
FCR - FIFO Control Register
Read/Write
Read-only
Write-only
LCR[7] = 0
011
LCR - Line Control Register
Read/Write
100
MCR - Modem Control Register
Read/Write
101
110
LSR - Line Status Register
MSR - Modem Status Register
Read-only
Read-only
LCR[7] = 0
111
SPR - Scratch Pad Register
Read/Write
19