;
; _8250.EQU            5.20A  June 8, 1995
;
; The Greenleaf Comm Library
;
; Copyright (C) 1991-94 Greenleaf Software Inc.  All Rights Reserved.
;
; NOTES
;
; This file contains the constant definitions for all of the 8250
; registers and bitfields.  It should directly correspond to _8250.H.
;
; MODIFICATIONS

;
;  The 8250 port offsets, relative to base (com1, com2, etc.)
;
BASE    equ     0
TXBUF   equ     0               ; Tx Buffer
RXBUF   equ     0               ; Rx Buffer
BRLSB   equ     0               ; baud rate LSB divisor latch
BRMSB   equ     1               ; baud rate MSB
INTER   equ     1               ; interrupt enable register
INTID   equ     2               ; interrupt ID register
FIFOCTL equ     2               ; 16550 FIFI control register
LCREG   equ     3               ; line control register
MCREG   equ     4               ; modem control reg
LSREG   equ     5               ; line status reg
MSREG   equ     6               ; modem status reg

; Equates for bits in the line control register

WLS0    equ     00000001b       ; word length select bit 0
WLS1    equ     00000010b       ; word length select bit 1
NSB     equ     00000100b       ; number stop bits
PAREN   equ     00001000b       ; parity enable
PAREVN  equ     00010000b       ; parity even
PARSTK  equ     00100000b       ; stick parity
SBREAK  equ     01000000b       ; send break
DLAB    equ     10000000b       ; set DLAB

; Equates for bits in Line Status register

DATARDY equ     00000001b       ; data ready
OVERRN  equ     00000010b       ; overrun error
PARERR  equ     00000100b       ; parity error
FRAMERR equ     00001000b       ; framing error
RBREAK  equ     00010000b       ; break interrupt (received break)
THRE    equ     00100000b       ; transmitter holding reg empty
TSRE    equ     01000000b       ; tx shift register empty

;  Equates for bits in Modem Control register

DTR     equ     00000001b       ; DTR
RTS     equ     00000010b       ; RTS
OUT1    equ     00000100b       ; aux signal "out1" (not used)
OUT2    equ     00001000b       ; ditto "out2"
LOOPIT  equ     00010000b       ; loop mode latch

;  Equates for bits in Modem Status register

DCTS    equ     00000001b       ; delta CTS
DDSR    equ     00000010b       ; delta DSR
TERI    equ     00000100b       ; trailing edge RI
DRLSD   equ     00001000b       ; delta Rx Line Signal Detect
CTS     equ     00010000b       ; CTS
DSR     equ     00100000b       ; DRS
RINGIN  equ     01000000b       ; RI
RLSD    equ     10000000b       ; Rx Line Signal Detect

;  Equates for bits in Interrupt Enable register

ENRX    equ     00000001b       ; enable Data Available int
ENTX    equ     00000010b       ; enable Tx Holding Reg Empty int
ENRXS   equ     00000100b       ; enable Rx Special Conditions int
ENMS    equ     00001000b       ; enable Modem Status Interrupt


