XR16V554_07 Datasheet, PDF (19/45 Pages) Exar Corporation – 2.25V TO 3.6V QUAD UART WITH 16-BYTE FIFO

XR16V554/554D
REV. 1.0.2
2.25V TO 3.6V QUAD UART WITH 16-BYTE FIFO
3.0 UART INTERNAL REGISTERS
Each UART channel in the V554 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 INTERNAL REGISTERS
A2,A1,A0 ADDRESSES
REGISTER
READ/WRITE
16C550 COMPATIBLE REGISTERS
000
RHR - Receive Holding Register
THR - Transmit Holding Register
Read-only
Write-only
000
DLL - Divisor LSB
Read/Write
001
DLM - Divisor MSB
Read/Write
001
IER - Interrupt Enable Register
Read/Write
010
ISR - Interrupt Status Register
FCR - FIFO Control Register
Read-only
Write-only
011
LCR - Line Control Register
Read/Write
100
MCR - Modem Control Register
Read/Write
101
LSR - Line Status Register
Read-only
110
MSR - Modem Status Register
Read-only
111
SPR - Scratch Pad Register
Read/Write
COMMENTS
LCR[7] = 0
LCR[7] = 1, LCR ≠ 0xBF
LCR[7] = 0
LCR[7] = 0
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