XR16M781 Datasheet, PDF (23/52 Pages) Exar Corporation – 1.62V TO 3.63V UART WITH 64-BYTE FIFO AND VLIO INTERFACE

XR16M781
REV. 1.0.1
1.62V TO 3.63V UART WITH 64-BYTE FIFO AND VLIO INTERFACE
3.0 UART INTERNAL REGISTERS
The complete register set for the M781 is shown in Table 6 and Table 7.
TABLE 6: UART INTERNAL REGISTERS
A2 A1 A0
ADDRESSES
REGISTER
READ/WRITE
COMMENTS
16C550 COMPATIBLE REGISTERS
0 00
0 01
DREV - Device Revision
DVID - Device Identification Register
Read-only
Read-only
LCR[7] = 1, LCR ≠ 0xBF,
DLL = 0x00, DLM = 0x00
0 00
0 01
DLL - Divisor LSB Register
DLM - Divisor MSB Register
Read/Write
Read/Write
LCR[7] = 1, LCR ≠ 0xBF
See DLD[7:6]
0 10
DLD - Divisor Fractional Register
Read/Write
LCR[7] = 1, LCR ≠ 0xBF,
EFR[4] = 1
0 00
0 01
RHR - Receive Holding Register
THR - Transmit Holding Register
IER - Interrupt Enable Register
Read-only
Write-only
Read/Write
LCR[7] = 0
0 10
ISR - Interrupt Status Register
FCR - FIFO Control Register
Read-only
Write-only
LCR[7] = 0 if EFR[4] = 1
or
LCR ≠ 0xBF if EFR[4] = 0
0 11
LCR - Line Control Register
Read/Write
1 00
MCR - Modem Control Register
Read/Write
1 01
LSR - Line Status Register
Read-only
LCR ≠ 0xBF
1 10
MSR - Modem Status Register
Read-only
1 10
MSR - Modem Status Register
Write-only
LCR ≠ 0xBF
EFR[4] = 1
1 11
SPR - Scratch Pad Register
Read/Write
LCR ≠ 0xBF, FCTR[6] = 0
1 11
1 11
EMSR - Enhanced Mode Select Register
FC - RX/TX FIFO Level Counter Register
Write-only
Read-only
LCR ≠ 0xBF, FCTR[6] = 1
ENHANCED REGISTERS
0 00
FC - RX/TX FIFO Level Counter Register
Read-only
0 00
TRIG - RX/TX FIFO Trigger Level Register
Write-only
0 01
FCTR - Feature Control Register
Read/Write
0 10
1 00
EFR - Enhanced Function Reg
Xon-1 - Xon Character 1
Read/Write
Read/Write
LCR = 0xBF
1 01
Xon-2 - Xon Character 2
Read/Write
1 10
Xoff-1 - Xoff Character 1
Read/Write
1 11
Xoff-2 - Xoff Character 2
Read/Write
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