XR16M752_09 Datasheet, PDF (24/54 Pages) Exar Corporation – HIGH PERFORMANCE DUART WITH 64-BYTE FIFO

XR16M752/XR68M752
HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
REV. 1.1.1
3.0 UART INTERNAL REGISTERS
Each of the UART channel in the M752 has its own set of configuration registers selected by address lines A0,
A1 and A2 with CSA# or CSB# selecting the channel. The complete register set is shown on Table 7 and
Table 8.
TABLE 7: UART CHANNEL A AND B UART INTERNAL REGISTERS
ADDRESSES
A2 A1 A0
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
0 01
DLL - Divisor LSB
DLM - Divisor MSB
Read/Write
Read/Write
LCR[7] = 1, LCR ≠ 0xBF
0 10
DLD - Divisor Fractional
Read/Write
LCR[7] = 1, LCR ≠ 0xBF,
EFR[4] = 1
0 01
0 10
IER - Interrupt Enable Register
ISR - Interrupt Status Register
FCR - FIFO Control Register
Read/Write
Read-only
Write-only
LCR[7] = 0
0 11
LCR - Line Control Register
Read/Write
1 00
1 01
MCR - Modem Control Register
LSR - Line Status Register
Read/Write
Read-only
LCR ≠ 0xBF
1 10
MSR - Modem Status Register
Read-only
See Table 13
1 11
SPR - Scratch Pad Register
Read/Write
See Table 12
1 10
TCR - Transmission Control Register
Read/Write
See Table 13
1 11
TLR - Trigger Level Register
Read/Write
See Table 12
1 11
FIFO Rdy - FIFO Ready Register
Read-only
See Table 12
ENHANCED REGISTERS
0 10
EFR - Enhanced Function Register
Read/Write
1 00
Xon-1 - Xon Character 1
Read/Write
1 01
Xon-2 - Xon Character 2
Read/Write
LCR = 0xBF
1 10
Xoff-1 - Xoff Character 1
Read/Write
1 11
Xoff-2 - Xoff Character 2
Read/Write
24