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Digital-Research-Source-Code/CPM OPERATING SYSTEMS/CPM 86/CONCURRENT/CCPM-86 3.1 SOURCE/D5/U2651.EQU
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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;********************************************************
;* 2651 Usart Commmand And Status port equates *
;* File Name: U2651.EQU *
;* Last Update: 2/10/83 *
;********************************************************
; usart's command registers bit equates
X_CTL equ 01H ; Set enables Xmitter
DTR equ 02H ; 1 forces the DTR pin low
R_CTL equ 04H ; Set enables the Receiver
ERROR_RESET equ 10H ; Setting this resets the error flags
RTS equ 20H ; 1 forces the RTS pin low
; usart's status register bit equates
TXRDY equ 01H ; Set = the Xmit buffer is empty
RXRDY equ 02H ; Set = the Recv buffer has data
PARITY_ERR equ 08H ; Set = parity error
OVERRUN_ERR equ 10H ; Set = overrun error
FRAME_ERR equ 20H ; Set = framing error
DCD equ 40H ; Set means DCD is low
DSR equ 80H ; Set means DSR is low