Compaq Contec COM-2(PC)F - Manual (Page 71)

Appendix
COM-2(PC)F
62
C. The Details on NS16550
Table 6.9. NS16550's Register
(Short from National Semiconductor's data book)
< 1 / 2 >
Register
0 DLAB = 0 0 DLAB = 0 1 DLAB = 0 2 2 3
Bit Receiver Transmitter Interrupt Interrupt FIFO Line
No. Buffer Holding Enable Ident. Control Control
Register Register Register Register Register Register
(Read Only) (Write Only) (Read Only) (Write Only)
RBR THR IER IIR FCR LCR
0 Data Bit 0 Data Bit 0 Enable "0" if FIFO Word
Received Interrupt Enable Length
Data Pending Select
Available Bit 0
Interrupt (WLS0)
(ERBFI)
1 Data Bit 1 Data Bit 1 Enable Interrupt RCVR Word
Transmitter ID FIFO Length
Holding Bit (0) Reset Select
Register Bit 1
Empty (WLS1)
Interrupt
(ETBEI)
2 Data Bit 2 Data Bit 2 Enable Interrupt XMIT Number of
Receiver ID FIFO Stop Bits
Line Status Bit (1) Reset (STB)
Interrupt
(ELSI)
3 Data Bit 3 Data Bit 3 Enable Interrupt DMA Parity
MODEM ID Mode Enable
Status Bit (2) Select (PEN)
Interrupt
(EDSSI)
4 Data Bit 4 Data Bit 4 0 0 Reserved Even
Parity
Select
(EPS)
5 Data Bit 5 Data Bit 5 0 0 Reserved Stick
Parity
6 Data Bit 6 Data Bit 6 0 FIFOs RCVR Set
Enabled Trigger Break
(LSB)
7 Data Bit 7 Data Bit 7 0 FIFOs RCVR Divisor
Enabled Trigger Latch
(MSB) Access Bit
(DLAB)