; con speed of TERMINAL link, there are three bottlenecks : ; 1- time to send XOFF/RTS_high on CR (CR+LF=EOL), first emergency. ; 2- the char loop time, ; 3- the time between sending XON/RTS_low and clearing UCRXIFG on first received char, ; everything must be done to reduce these times, taking into account the necessity of switching to SLEEP (LPMx mode). ; --------------------------------------; ; (ACCEPT) part I: prepare TERMINAL_INT ; ; --------------------------------------; MOV #ENDACCEPT,S ;2 S = ACCEPT XOFF return MOV #AKEYREAD1,T ;2 T = default XON return .word 152Dh ;5 PUSHM IP,S,T, as IP ret, XOFF ret, XON ret MOV TOS,W ;1 -- addr len MOV @PSP,TOS ;2 -- org ptr ) ADD TOS,W ;1 -- org ptr W=Bound ) MOV #0Dh,T ;2 T = 'CR' to speed up char loop in part II > prepare stack and registers MOV #20h,S ;2 S = 'BL' to speed up char loop in part II ) for TERMINAL_INT use BIT #UCRXIFG,&TERMIFG ;3 RX_Int ? JZ ACCEPTNEXT ;2 no : case of quiet input terminal MOV &TERMRXBUF,Y ;3 yes: clear RX_Int CMP #0Ah,Y ;2 received char = LF ? (end of downloading ?) JNZ RXON ;2 no : RXON return = AKEYREAD1, to process first char of new line. ACCEPTNEXT ADD #2,RSP ;1 yes: remove AKEYREAD1 as XON return, MOV #SLEEP,X ;2 and set XON return = SLEEP .word 153Ch ;6 PUSHM S,T,W,X before SLEEP (and so WAKE on any interrupts) ; --------------------------------------; RXON ; ; --------------------------------------; .IFDEF TERMINAL3WIRES ; RXON_LOOP BIT #UCTXIFG,&TERMIFG ;3 wait the sending end of XON, useless at high baudrates JZ RXON_LOOP ;2 MOV #17,&TERMTXBUF ;4 move char XON into TX_buf .ENDIF ; .IFDEF TERMINAL4WIRES ; BIC.B #RTS,&HANDSHAKOUT ;4 set RTS low .ENDIF ; ; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv; ; starts first and 3th stopwatches ; ; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^; RET ;4 to SLEEP (End of file download or quiet input) or AKEYREAD1 (get next line of file downloading) ; --------------------------------------; ; --------------------------------------; RXOFF ; ; --------------------------------------; .IFDEF TERMINAL3WIRES ; RXOFF_LOOP BIT #UCTXIFG,&TERMIFG ;3 wait the sending end of XOFF, useless at high baudrates JZ RXOFF_LOOP ;2 MOV #19,&TERMTXBUF ;4 move XOFF char into TX_buf .ENDIF ; .IFDEF TERMINAL4WIRES ; BIS.B #RTS,&HANDSHAKOUT ;4 set RTS high .ENDIF ; RET ;4 to ENDACCEPT ; --------------------------------------; ; --------------------------------------; ASMWORD "SLEEP" ; may be redirected SLEEP ; MOV #PARENSLEEP,PC ;3 ; --------------------------------------; ; --------------------------------------; ASMWORD "(SLEEP)" ; PARENSLEEP ; BIS &LPM_MODE,SR ;3 enter in LPMx sleep mode with GIE=1 ; --------------------------------------; default FAST FORTH mode (for its input terminal use) : LPM0. ;############################################################################################################### ;############################################################################################################### ; ### # # ####### ####### ###### ###### # # ###### ####### ##### # # ####### ###### ####### ; # ## # # # # # # # # # # # # # # # # # # # # ; # # # # # # # # # # # # # # # # # # # # # # ; # # # # # ##### ###### ###### # # ###### # ##### ####### ##### ###### ##### ; # # # # # # # # # # # # # # # # # # # # # ; # # ## # # # # # # # # # # # # # # # # # # ; ### # # # ####### # # # # ##### # # ##### # # ####### # # ####### ;############################################################################################################### ;############################################################################################################### ; here, Fast FORTH sleeps, waiting any interrupt. ; IP,S,T,W,X,Y registers (R13 to R8) are free for any interrupt routine... ; ...and so PSP and RSP stacks with their rules of use. ; remember: in any interrupt routine you must include : BIC #0x78,0(RSP) before RETI ; to force return to SLEEP. ; or (bad idea ? previous SR flags are lost) simply : ADD #2 RSP, then RET instead of RETI ; ======================================; JMP SLEEP ;2 here is the return for any interrupts, else TERMINAL_INT :-) ; ======================================; ; **************************************; TERMINAL_INT ; <--- TEMR RX interrupt vector, delayed by the LPMx wake up time ; **************************************; if wake up time increases, max bauds rate decreases... ; (ACCEPT) part II under interrupt ; Org Ptr -- len' ; --------------------------------------; ADD #4,RSP ;1 remove SR and PC from stack, SR flags are lost (unused by FORTH interpreter) .word 172Ah ;5 POPM W=buffer_bound,T=0Dh,S=20h ; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv; ; starts the 2th stopwatch ; ; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^; AKEYREAD MOV.B &TERMRXBUF,Y ;3 read character into Y, UCRXIFG is cleared ; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv; ; stops the 3th stopwatch ; 3th bottleneck result : 17~ + LPMx wake_up time ( + 5~ XON loop if F/Bds<230401 ) ; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^; AKEYREAD1 ; <--- XON RET address 2 ; first emergency: anticipate XOFF on CR as soon as possible CMP.B T,Y ;1 char = CR ? JZ RXOFF ;2 then RET to ENDACCEPT ; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv;+ 4 to send RXOFF ; stops the first stopwatch ;= first bottleneck (empty line process), best case result: 20~ + LPMx wake_up time.. ; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^; ...or 11~ in case of empty line CMP.B S,Y ;1 printable char ? JHS ASTORETEST ;2 yes CMP.B #8,Y ; char = BS ? JNE WAITaKEY ; case of other control chars ; --------------------------------------; ; start of backspace ; made only by an human ; --------------------------------------; CMP @PSP,TOS ; Ptr = Org ? JZ WAITaKEY ; yes: do nothing else SUB #1,TOS ; no : dec Ptr JMP WAITaKEY ; --------------------------------------; ; end of backspace ; ; --------------------------------------; ASTORETEST CMP W,TOS ; 1 Bound is reached ? JZ WAITaKEY ; 2 yes: loopback MOV.B Y,0(TOS) ; 3 no: store char @ Ptr, send echo then loopback ADD #1,TOS ; 1 increment Ptr ; --------------------------------------; WAITaKEY BIT #UCRXIFG,&TERMIFG ; 3 new char in TERMRXBUF ? JNZ AKEYREAD ; 2 yes JZ WAITaKEY ; 2 no ; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv; ; stops the 2th stopwatch ; best case result: 23~ ==> 434 kBds/MHz ; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^; ; --------------------------------------; ENDACCEPT ; <--- XOFF return address ; --------------------------------------; MOV #LPM0+GIE,&LPM_MODE ; reset LPM_MODE to default mode LPM0 for next line of input stream CMP #0,&LINE ; if LINE <> 0... JZ DROPEXIT ; ADD #1,&LINE ; ...increment LINE DROPEXIT SUB @PSP+,TOS ; Org Ptr -- len' MOV @RSP+,IP ; 2 and continue with INTERPRET with GIE=0. ; So FORTH machine is protected against any interrupt... mNEXT ; ...until next falling down to LPMx mode of (ACCEPT) part1, ; **************************************; i.e. when the FORTH interpreter has no more to do. ; ------------------------------------------------------------------------------ ; TERMINAL I/O, output part ; ------------------------------------------------------------------------------ ;Z (EMIT) c -- output character (byte) to the terminal ; hardware or software control on TX flow seems not necessary with UARTtoUSB bridges because ; they stop TX when their RX buffer is full. So no problem when the terminal input is echoed to output. FORTHWORD "(EMIT)" PARENEMIT MOV TOS,Y ; 1 MOV @PSP+,TOS ; 2 YEMIT1 BIT #UCTXIFG,&TERMIFG ; 3 wait the sending end of previous char, useless at high baudrates JZ YEMIT1 ; 2 .IFDEF TERMINAL5WIRES ; YEMIT2 BIT.B #CTS,&HANDSHAKIN ; JNZ YEMIT2 .ENDIF YEMIT .word 4882h ; hi7/4~ lo:12/4~ send/send_not echo to terminal .word TERMTXBUF ; 3 MOV Y,&TERMTXBUF mNEXT ; 4