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Assembly Source File | 1986-12-29 | 28.7 KB | 780 lines

page 60,132 ;*********************************************************** ;** ** ;** Device Driver for RS232 communications ** ;** TI PC Version ** ;** Copyright (C) Texas Instruments 1986 ** ;** Author: Greg Haley ** ;** ** ;** THIS SOURCE CODE MAY BE DISTRIBUTED AND MODIFIED ** ;** ONLY IF THE ORIGINAL COPYRIGHT AND AUTHOR CREDITS ** ;** REMAIN INTACT. ** ;** ** ;** Project Start Date: 11/20/86 ** ;** ** ;** RE: 12/29/86 by Greg Haley ** ;** Added send_xon routine. ** ;** Added TI internal modem support. ** ;** Added 19200 baud. ** ;** ** ;*********************************************************** name tirs232 title Device Driver for TI PC Communications code segment byte assume cs:code,ds:nothing,es:nothing include rs232.inc page ;*********************************************************** ;** Keyboard Routines ** ;*********************************************************** keyboard equ 4ah ; TI PC keyboard INT altah db 0 ; Storage for high byte of key input k_ready: mov al,cs:altah ; Get 2nd half of F-key? or al,al jnz k_rdy_xit ; Yes, skip to end mov ah,1 ; Is a char waiting? int keyboard jz k_rdy_xit ; No, exit or ax,ax ; If it was a ^C, remove it jnz k_rdy_xit xor ah,ah int keyboard jmp short k_ready ; And try again k_rdy_xit: ret k_read: xor ax,ax ; Clear AX xchg al,cs:altah ; Get 2nd half of F-key? or al,al jnz k_r_xit ; Yes, skip to end k_r_1: xor ah,ah int keyboard or ax,ax ; Was it a ^C? jz k_r_1 ; Yes, get another or al,al ; Is it a F-key? jnz k_r_xit ; No, exit mov cs:altah,ah ; Yes, save 2nd half k_r_xit: ret page ;*********************************************************** ;** Communications Routines ** ;*********************************************************** recv_size equ 800h ; Receive buffer size ; Must be one of these values: ; 0004h = 4 bytes ; 0008h = 8 bytes ; 0010h = 16 bytes ; 0020h = 32 bytes ; 0040h = 64 bytes ; 0080h = 128 bytes ; 0100h = 256 bytes ; 0200h = 512 bytes ; 0400h = 1024 bytes ; 0800h = 2048 bytes ; 1000h = 4096 bytes ; 2000h = 8192 bytes ; 4000h = 16384 bytes ; 8000h = 32768 bytes recv_limit equ not recv_size ; Receive buffer limit mask busy_len equ recv_size *3 /4 ; Go busy at 3/4 buf length not_busy_len equ recv_size /2 ; Not busy at 1/2 buf length int_controller equ 19h ; 8259A Interrupt Controller port int_ack equ 18h ; 8259A Interrupt Acknowledge port EOI equ 00100000b ; Non-specific EOI enable_ints equ 01000000b ; Enable interrupts disable_ints equ 11000000b ; Disable interrupts dtr_bit equ 1 ; DTR bit in uart control register rts_bit equ 2 ; DTR bit in uart control register dcd_bit equ 1 ; DCD bit in modem status register cts_bit equ 2 ; CTS bit in modem status register dsr_bit equ 4 ; DSR bit in modem status register scf_bit equ 8 ; SCF bit in modem status register ri_bit equ 16 ; RI bit in modem status register xon equ 11h ; xmit on busy char xoff equ 13h ; xmit off busy char page ;*********************************************************** ;** Variables ** ;*********************************************************** old_ss dw 0 ; Old SS reg old_sp dw 0 ; Old SP reg db 80 dup (?) ; Stack i_stack label byte rq_head dw 0 ; Receive Queue start rq_tail dw 0 ; Receive Queue stop rq_len dw 0 ; Current receive Queue length rqueue db recv_size dup (?) ; Receive queue oldseg dw 0 ; Old segment for int vector oldoff dw 0 ; Old offset for int vector busy_hand db 0 ; busy handling type r_busy db 0 ; recv busy flag t_busy db 0 ; xmit busy flag xmit_busy db 0 ; xmit busy flag (for ints) m_stat db 0 ; Current modem status l_stat db 0 ; Current line status dcw dw 1100000001010000b ; default 2400, 8, N, 1 parity_on db 0 ; Parity flag ti_modem db 0 ; Flag for TI internal modem opn_tbl: db 0 ; Needs leading 0 for sync db 9 ; select reg 9 db 01001001b ; Reset chan B, MIE, & VIS db 12 ; select reg 12 baudl db 30 ; Low byte of baud rate (2400) db 13 ; select reg 13 baudh db 0 ; High byte of baud rate db 2 ; select reg 2 db 0 ; int vector on db 11 ; select reg 11 db 01010010b ; brate generator db 14 ; select reg 14 db 00000011b ; enable brate gen. db 4 ; select reg 4 par_stp db 01000100b ; No parity, 1 stop bit db 3 ; select reg 3 recv_b db 11000001b ; recv enable, 8 bits db 5 ; select reg 5 xmit_b db 11101010b ; xmit enable, DTR, 8 bits db 10 ; select reg 10 db 0 ; NRZ, flags db 15 ; select reg 15 db 00101000b ; CTS, DCD int enable db 1 ; select reg 1 db 00010111b ; int enable opn_size equ $-opn_tbl opn2_tbl: db 0 ; Sync byte db 15 ; select reg 15 db 00101000b ; RI & DSR int enable db 1 ; select reg 1 db 00000001b ; external int enable opn2_size equ $-opn2_tbl int_tbl dw 0 ; Interrupt branch table dw mod_stat dw 0 dw 0 dw xmit_mt dw mod_stat dw rec_full dw lin_stat ; table for baud rate constants baud_tbl dw 696 ; 110 dw 510 ; 150 dw 254 ; 300 dw 126 ; 600 dw 62 ; 1200 dw 30 ; 2400 dw 14 ; 4800 dw 6 ; 9600 ; table for port number init tables p_table dw port1_tbl dw port2_tbl dw port3_tbl dw port4_tbl port_n dw port1_tbl ; default port is 1 ; port 1 init table port1_tbl dw 40h ; Interrupt vector for irq db 11111110b ; Mask to enable irq db 00000001b ; Mask to unable irq dw 0e7h ; Receive buffer port dw 0e7h ; Transmit buffer port dw 0e6h ; 8530 UART Control port dw 0e6h ; 8530 UART Status port dw 0e4h ; 8530 Modem Status port dw 0e6h ; 8530 interrupt enable register dw 0e0h ; 8530 interrupt ack register p_tbl_size equ $-port1_tbl ; port 2 init table port2_tbl dw 41h ; Interrupt vector for irq db 11111101b ; Mask to enable irq db 00000010b ; Mask to unable irq dw 0efh ; Receive buffer port dw 0efh ; Transmit buffer port dw 0eeh ; 8530 UART Control port dw 0eeh ; 8530 UART Status port dw 0ech ; 8530 Modem Status port dw 0eeh ; 8530 interrupt enable register dw 0e8h ; 8530 interrupt ack register ; port 3 init table port3_tbl dw 42h ; Interrupt vector for irq db 11111011b ; Mask to enable irq db 00000100b ; Mask to unable irq dw 0f7h ; Receive buffer port dw 0f7h ; Transmit buffer port dw 0f6h ; 8530 UART Control port dw 0f6h ; 8530 UART Status port dw 0f4h ; 8530 Modem Status port dw 0f6h ; 8530 interrupt enable register dw 0f0h ; 8530 interrupt ack register ; port 4 init table port4_tbl dw 44h ; Interrupt vector for irq db 11101111b ; Mask to enable irq db 00010000b ; Mask to unable irq dw 0ffh ; Receive buffer port dw 0ffh ; Transmit buffer port dw 0feh ; 8530 UART Control port dw 0feh ; 8530 UART Status port dw 0fch ; 8530 Modem Status port dw 0feh ; 8530 interrupt enable register dw 0f8h ; 8530 interrupt ack register ; defaults for port 1 port_tbl label word comm1_vector dw 40h ; Interrupt vector for irq irq_enab_mask db 11111110b ; Mask to enable irq irq_unab_mask db 00000001b ; Mask to unable irq recv_buffer dw 0e7h ; Receive buffer port send_buffer dw 0e7h ; Transmit buffer port uart_control dw 0e6h ; 8530 UART Control port uart_status dw 0e6h ; 8530 UART Status port modem_status dw 0e4h ; 8530 Modem Status port int_enable dw 0e6h ; 8530 interrupt enable register ack_int dw 0e0h ; 8530 interrupt ack register page ;*********************************************************** ;** Subroutine to set up comm chip per the DCW ** ;** DCW is in AX ** ;*********************************************************** set_dcw: ; set parity type mov bl,al ; get low byte in BL and bl,00000011b ; mask unused bits and byte ptr par_stp,11111100b ; reset parity or byte ptr par_stp,bl ; change parity and bl,00000001b ; change parity flag mov byte ptr parity_on,bl ; ; set num stop bits mov bl,al ; get low byte in BL and bl,00001000b ; mask unused bits or bl,00000100b ; 1.5 stop bits not used and byte ptr par_stp,11110011b ; reset stop bits or byte ptr par_stp,bl ; change stop bits ; set baud rate mov bl,al ; get low byte in BL and bl,01110000b ; mask unused bits mov cl,3 ; shift to make word ptr shr bl,cl mov si,offset baud_tbl ; point to baud table xor bh,bh ; make BX a byte ptr add si,bx ; SI now points to baud rate const mov dx,word ptr [si] ; get baud rate in DX mov byte ptr baudl,dl ; save low byte of baud rate mov byte ptr baudh,dh ; save high byte of baud rate ; set busy type mov bl,ah and bl,00000011b ; mask unwanted bits mov byte ptr busy_hand,bl ; store it ; set port number mov bl,ah ; get high byte in BL and bl,00011000b ; mask unused bits shr bl,1 ; shift to make word ptr shr bl,1 mov si,offset p_table ; point to port table xor bh,bh ; make BX a byte ptr add si,bx ; SI now points to baud rate const mov dx,word ptr [si] ; get port adrs in DX mov word ptr port_n,dx ; save port number adrs ; set data bits mov bl,ah ; get high byte in BL and bl,01000000b ; mask unused bits or bl,00100000b ; make it at least 7 bits and byte ptr xmit_b,10011111b ; reset xmit data size or byte ptr xmit_b,bl ; set xmit data size shl bl,1 ; adjust for recv data size and byte ptr recv_b,00111111b ; reset recv data size or byte ptr recv_b,bl ; set recv data size ; Check for internal modem mov ti_modem,al and ti_modem,00000100b ; TI internal modem if not 0 ret page ;*********************************************************** ;** Subroutine to set up interrupt vector ** ;** and initialize the 8530 comm chip ** ;*********************************************************** init_comm: push ds push cs pop ds ; get correct port parameters push es push cs pop es mov si,word ptr port_n ; get port table adrs mov di,offset port_tbl ; DI points to table to use mov cx,p_tbl_size ; CX has table length repz movsb ; move it pop es ; Save old int vector for irq mov di,comm1_vector call get_vector mov word ptr oldseg,bx mov word ptr oldoff,dx ; Set up int vector for irq push cs ; Make BX = CS pop bx mov dx,offset isr mov di,comm1_vector call set_vector ; Enable irq from 8259A cli in al,int_controller jmp $+2 ; delay and al,irq_enab_mask out int_controller,al ; Read receive buffer register mov dx,recv_buffer in al,dx ; Read modem status register call mod_stat ; Read UART status register call lin_stat ; open 8530 mov si,offset opn_tbl mov cx,opn_size mov dx,uart_control init_1: lodsb out dx,al jmp $+2 ; delay loop init_1 mov si,offset opn2_tbl mov cx,opn2_size mov dx,modem_status init_2: lodsb out dx,al jmp $+2 ; delay loop init_2 pop ds sti ; Reset TI internal modem if present cmp cs:byte ptr ti_modem,0 ; TI internal modem? jz no_ti_modem ; No, exit mov dx,modem_status ; Yes, set /RCNTL mov al,5 out dx,al mov al,cs:xmit_b or al,2 out dx,al wait_4_ack: mov dx,uart_status ; Check for ACK mov al,10h out dx,al jmp $+2 ; delay jmp $+2 ; delay in al,dx test al,10h ; Got an ACK? jz wait_4_ack ; No, keep looping no_ti_modem: ret page ;*********************************************************** ;** Subroutine to restore interrupt vector ** ;** and reset the 8530 comm chip ** ;*********************************************************** de_init: cli ; Disable interrupts on 8530 and drop DTR, RTS mov dx,cs: word ptr int_enable mov al,9 ; select reg 9 out dx,al mov al,disable_ints jmp $+2 ; delay out dx,al jmp $+2 ; delay jmp $+2 ; delay ; Disable irq in al,int_controller or al,cs:byte ptr irq_unab_mask jmp $+2 ; delay jmp $+2 ; delay out int_controller,al ; It's probably not a good idea to restore the vector at close in ; this case, but here's the code to do it: ; ; Restore int vector for irq ; mov bx,cs:word ptr oldseg ; mov dx,cs:word ptr oldoff ; mov di,comm1_vector ; call set_vector sti ret page ;*********************************************************** ;** Interrupt Service Routine ** ;*********************************************************** isr: cli cld ; Set up new stack mov cs:word ptr old_sp,sp mov cs:word ptr old_ss,ss mov sp,cs mov ss,sp mov sp,offset i_stack push ax push bx push cx push dx push ds push cs pop ds ; Verify int came from 8530 mov dx,uart_status mov al,3 ; reg 3 out dx,al ; select reg 3 jmp $+2 ; delay jmp $+2 ; delay in al,dx ; read reg 3 or al,al ; Interrupt pending? jz isr_exit ; No, exit ; Acknowledge int mov dx,ack_int ; get int ack reg xor al,al ; 1st write a 0 out dx,al jmp $+2 ; delay jmp $+2 ; delay in al,dx ; get int type ; Branch to correct routine cbw ; make int type a word mov bx,offset int_tbl ; point to int table add bx,ax ; add int type sti call cs:word ptr [bx] ; go do subroutine cli ; Reset highest int under service by 8530 mov al,00111000b ; reset highest int code mov dx,int_enable ; select port out dx,al ; reset the int jmp $+2 ; delay isr_exit: ; Tell 8259A we're done mov al,EOI out int_ack,al pop ds pop dx pop cx pop bx pop ax ; restore stack mov ss,cs:word ptr old_ss mov sp,cs:word ptr old_sp sti iret page ;*********************************************************** ;** Subroutine to read the modem status ** ;*********************************************************** mod_stat: mov dx,modem_status ; Read modem status (CHB) xor al,al ; reg 0 out dx,al ; Select reg 0 jmp $+2 ; delay jmp $+2 ; delay in al,dx ; read reg 0 mov cl,5 ; move bits to AH shl ax,cl xor al,al ; Read reg 0 mov dx,modem_status ; Read modem status (CHB) inc dx ; adjust to channel A inc dx out dx,al ; Select reg 0 jmp $+2 ; delay jmp $+2 ; delay in al,dx ; into reg AL shl al,1 ; adjust to match ACS lib shl al,1 shl ax,1 shl al,1 shl ax,1 and ah,00011111b ; mask unwanted bits ; AH now contains the line signals ; --------------------------------- ; | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ; --------------------------------- ; | | | | RI|SCF|DSR|CTS|DCD| ; --------------------------------- ; 0=down, 1=up mov cs:byte ptr m_stat,ah ; Update current modem status ; Check for busy handling shr ah,1 ; DSR in bit 0 shr ah,1 cmp cs:byte ptr busy_hand,2 ; DSR busy handling? jne chk_4scf ; No, skip mov al,ah ; save AH jmp set_tbusy ; go set or reset busy chk_4scf: cmp cs:byte ptr busy_hand,1 ; SCF busy handling? jne rst_sts ; No, skip shr ah,1 mov al,ah ; save AH set_tbusy: and al,1 ; up = busy on ; not al ; down = busy on mov cs:byte ptr t_busy,al ; set busy ; reset ext stat int rst_sts: mov al,10h ; reset ext sts code mov dx,modem_status ; reset chan B out dx,al jmp $+2 ; delay mov dx,uart_control ; reset chan A out dx,al ret page ;*********************************************************** ;** Subroutine to send the next char in queue ** ;*********************************************************** xmit_mt: mov cs:byte ptr xmit_busy,0 ; We're not busy ; reset xmit int mov al,00101000b ; code mov dx,uart_control out dx,al ret page ;*********************************************************** ;** Subroutine to receive a char and queue it ** ;*********************************************************** rec_full: mov dx,recv_buffer ; Get char in al,dx cmp cs:byte ptr parity_on,0 ; parity? jz no_par ; No, don't mask off parity bit and al,7fh ; Yes, mask off parity bit no_par: ; check for XON-XOFF busy char cmp cs:byte ptr busy_hand,3 ; XON-XOFF busy handling? jne queue_char ; No, skip busy handling cmp al,xoff ; Need to set busy? jne chk_r_xon ; No, skip mov cs:byte ptr t_busy,1 ; set busy jmp xit_rec_full ; We're done chk_r_xon: cmp al,xon ; Need to reset busy? jne queue_char ; No, skip busy handling mov cs:byte ptr t_busy,0 ; reset busy jmp xit_rec_full ; We're done queue_char: ; check for buffer overflow cmp cs:word ptr rq_len,recv_limit ; buffer full? jb buf_full1 ; No, skip inc cs:word ptr rq_tail ; Yes, lose 1 char and cs:word ptr rq_tail,recv_limit dec cs:word ptr rq_len ; Adjust queue length buf_full1: mov bx,offset rqueue ; Queue char mov dx,cs:word ptr rq_head add bx,dx mov cs:byte ptr [bx],al inc dx and dx,recv_limit ; wrap if >= receive size mov cs:word ptr rq_head,dx inc cs:word ptr rq_len ; Adjust queue length ; set busy if needed cmp cs:byte ptr busy_hand,3 ; XON-XOFF busy handling? jne set_rb_done ; No, skip cmp cs:word ptr rq_len,busy_len ; Need to set busy? jb set_rb_done ; No, skip mov cs:byte ptr r_busy,1 ; set busy flag mov dx,cs:word ptr send_buffer ; send XOFF char mov al,xoff out dx,al set_rb_done: xit_rec_full: ret page ;*********************************************************** ;** Subroutine to send an xon char if needed ** ;*********************************************************** send_xon: cmp cs:byte ptr busy_hand,3 ; XON-XOFF busy handling? jne xit_send_xon ; No, skip mov dx,cs:word ptr send_buffer ; send XON char mov al,xon out dx,al xit_send_xon: ret page ;*********************************************************** ;** Subroutine to read the line status ** ;*********************************************************** lin_stat: mov dx,uart_status mov al,1 ; select reg 1 out dx,al jmp $+2 ; delay jmp $+2 ; delay in al,dx ; read status mov cs:byte ptr l_stat,al ; Update current line status ; reset error mov al,00110000b ; reset lin stat error code out dx,al ret page ;*********************************************************** ;** Subroutine to get an interrupt vector ** ;** ** ;** di = vector number ** ;** ** ;** Return: ** ;** bx = segment ** ;** dx = offset ** ;*********************************************************** get_vector: push es xor ax,ax mov es,ax shl di,1 shl di,1 mov dx,es:word ptr[di] mov bx,es:word ptr[di+2] pop es ret page ;*********************************************************** ;** Subroutine to set an interrupt vector ** ;** ** ;** di = vector number ** ;** bx = segment ** ;** dx = offset ** ;*********************************************************** set_vector: push es xor ax,ax mov es,ax shl di,1 shl di,1 mov es:word ptr[di],dx mov es:word ptr[di+2],bx pop es ret page ;*********************************************************** ;** Everything past here is truncated after install ** ;*********************************************************** init proc near lds bx,cs:[ptrsav] mov word ptr [bx].trans,offset init ;set break address mov [bx].trans+2,cs print_init: push cs pop ds mov dx,offset init_msg mov ah,9 int 21h jmp exit init endp init_msg: db cr,lf,'TI PC Communications Driver v2.51' db ' Copyright (C) Texas Instruments 1986' db cr,lf,'Written by ' db 'Greg Haley' db cr,lf,cr,lf,'$' code ends end