; SX4Amiga ; ; Programmer for the SX microcontrollers from Scenix ; ; Version 0.2ß ; By Dennis van Weeren ; 2000(C) ; ; 18-06-2000: ; Added watchdog to prevent hanging ; Changed timing to support newer revision SX ; ; Pic16C/F84-10P ; Osc.= HS, 9.8304 MHz, WatchDog ON #define PAGE0 bcf STATUS,RP0 #define PAGE1 bsf STATUS,RP0 ;Variables flags equ 0x0c Wstack equ 0x0d Sstack equ 0x0e countin equ 0x0f shiftin equ 0x10 bitin equ 0x11 bitout equ 0x12 shiftout equ 0x13 countout equ 0x14 buffer equ 0x15 counter equ 0x16 timer equ 0x17 char equ 0x18 datawrhi equ 0x19 datawrlo equ 0x1a datawr_c_hi equ 0x1b datawr_c_lo equ 0x1c datardhi equ 0x1d datardlo equ 0x1e repeats equ 0x1f tmp equ 0x20 ;Flag Constants send equ 0 receive equ 1 buf equ 2 pcal equ 3 ;Serial constants 19200 baud @ 9.8304Mhz Baudrate equ 0xce ; baudclockratecount Baudcount equ 0x02 ; counts per full baud Halfcount equ 0x01 ; counts per half baud ;I/O constants PORTA OSC1_GND equ 1 OSC1_VPP equ 2 OSC1_VCC equ 3 ;some more constants for porta osc1 control OSC1HIGH equ 0x08 OSC1LOW equ 0x02 OSC1VPP equ 0x04 OSC1FLOAT equ 0x00 ;I/O constants PORTB rxd equ 0 txd equ 1 OSC2 equ 3 LED equ 4 ;--------------ProgramStart--------------- org 0x000 goto Init nop nop nop goto Int_Service Init movlw 0x12 ;set initial I/O conditions movwf PORTB movlw OSC1FLOAT movwf PORTA PAGE1 movlw 0x8c ;WDT prescaler to 1:16 -->0.3s timeout movwf OPTION_REG ;RTCC to 1:1 internal cycle INT on falling edge movlw 0x09 ;set DDR/TRIS movwf TRISB movlw 0x00 movwf TRISA PAGE0 clrf flags bcf INTCON,INTF ;switch on serial INT bsf INTCON,INTE bcf INTCON,T0IF bsf INTCON,T0IE bsf INTCON,GIE ;CHECK WATCHDOG btfss STATUS,NOT_TO goto Error ;We were reset by the watchdog, error occurred ! ;END OF CHECK WATCHDOG Main bsf PORTB,LED call GetSerial ;wait for an Amiga command movwf char bcf PORTB,LED movf char,W ;s=start isp xorlw 0x73 btfsc STATUS,Z call StartISP movf char,W ;q=stop isp xorlw 0x71 btfsc STATUS,Z call StopISP movf char,W ;c=command xorlw 0x63 btfsc STATUS,Z call DoCommand clrf char ;clear command buffer goto Main ;----------ERROR Handling-------------------- Error clrwdt movlw 0x72 ;send r=error call SendSerial movf char,W ;Were we in the middle of a DoCommand ? xorlw 0x63 btfss STATUS,Z goto Main ;No, goto Main movlw 0x30 ;Send four zero's to finish DoCommand call SendSerial movlw 0x30 call SendSerial movlw 0x30 call SendSerial movlw 0x30 call SendSerial clrf char goto Main ;----------USER comm routines--------------------- StartISP call GoISP call SyncISP ;if GoISP was succesfull, there should be sync pulses xorlw 0x01 btfsc STATUS,Z goto StartFAIL movlw 0x6f ;send o=ok call SendSerial return StartFAIL movlw 0x72 ;send r=error call SendSerial return StopISP call ExitISP movlw 0x6f ;send o=ok call SendSerial return DoCommand call GetSerial ;get hi part of repeats call AscToHex movwf repeats ;put hi part in right nibble swapf repeats,F call GetSerial ;get lo part of repeats call AscToHex iorwf repeats,F ;combine both nibbles call GetSerial ;get hi part of datawrhi call AscToHex movwf datawrhi ;put hi part in right nibble swapf datawrhi,F call GetSerial ;get lo part of datawrhi call AscToHex iorwf datawrhi,F ;combine both nibbles call GetSerial ;get hi part of datawrlo call AscToHex movwf datawrlo ;put hi part in right nibble swapf datawrlo,F call GetSerial ;get lo part of datawrlo call AscToHex iorwf datawrlo,F ;combine both nibbles call GoFrame ;do the command xorlw 0x01 ;error ocurred ? btfsc STATUS,Z goto DoComFAIL movlw 0x6f ;send o=ok call SendSerial goto DoComData DoComFAIL movlw 0x72 ;send r=error call SendSerial goto DoComData DoComData swapf datardhi,W ;send hi nibble of datardhi call HexToAsc call SendSerial movf datardhi,W ;send lo nibble of datardhi call HexToAsc call SendSerial swapf datardlo,W ;send hi nibble of datardlo call HexToAsc call SendSerial movf datardlo,W ;send lo nibble of datardlo call HexToAsc call SendSerial return ;------------------------------------------------- ;----------------ISP support routines------------- ;------------------------------------------------- ;-----------Enter the ISP mode------------------------- GoISP call IntOFF movlw OSC1LOW ;pull osc1 low movwf PORTA bcf PORTB,OSC2 PAGE1 bcf TRISB,OSC2 ;pull osc2 low PAGE0 movlw 0xff call Delay ;delay for ~1000 cycles (more than 9 32khz cycles) movlw 0x0f ;toggle OSC1 16 times, just to be sure movwf counter ToggleLp movlw OSC1HIGH movwf PORTA ;set osc1 high movlw 0x30 call Delay ;delay 48*2 =about 24 khz togglerate movlw OSC1LOW ;set osc1 low movwf PORTA movlw 0x30 call Delay decfsz counter goto ToggleLp PAGE1 bsf TRISB,OSC2 ;release the osc2 pin PAGE0 movlw OSC1VPP movwf PORTA ;apply the programming voltage call IntON return ;---------Do a command, write and read------------ ;timing: ; ;Sync overhead is 2 to 5 cycles ; ;place data after 16 cycles (6.7us) ;sample data after 34 cycles (14us) ;remove data after 56 cycles (23us) ; ;this should work on SX chips varying from 90-150KHZ ; ;datawrhi,lo contains command and data to be written ;datardhi,lo contains data read back from the SX ;repeats contains the number of times this command should be issued ; ;returns 0x00 if OK, 0x01 if an error occurred GoFrame call IntOFF movf datawrhi,W ;copy data movwf datawr_c_hi movf datawrlo,W movwf datawr_c_lo call SyncISP ;synchronize to the SX frame movlw 0x10 ;4 commandbits and 12 databits --> 16 bits in total movwf counter xorlw 0x01 ;synchronization OK ? btfsc STATUS,Z goto FrameFAIL ;no, exit with errorcode FrameLP btfsc PORTB,OSC2 ;wait for the sync pulse goto FrameLP nop ;3 nop ;4 nop ;5 nop ;6 nop ;7 nop ;8 nop ;9 nop ;10 nop ;11 nop ;12 bcf PORTB,OSC2 ;set osc2 outputbuffer low PAGE1 btfss datawr_c_hi,7 bcf TRISB,OSC2 ;pull osc2 low by enabling output driver on 16 cycles PAGE0 rlf datawr_c_lo ;shift new databit into place rlf datawr_c_hi nop ;20 nop ;21 nop ;22 nop ;23 nop ;24 nop ;25 nop ;26 nop ;27 nop ;28 nop ;29 nop ;30 rlf datardlo ;shift old databits into place rlf datardhi bcf datardlo,0 ;sample OSC2 data on 34 cycles btfsc PORTB,OSC2 bsf datardlo,0 movlw 0x03 ;delay for 16 cycles inc. movlw call Delay nop ;52 nop ;53 nop ;54 PAGE1 bsf TRISB,OSC2 ;release the osc2 pin on 56 cycles PAGE0 FrameWOH btfss PORTB,OSC2 ;Wait for OSC2 to get high again goto FrameWOH decfsz counter ;last bit ? goto FrameLP ;no, do next bit decf repeats btfsc STATUS,Z ;last repeat? goto FrameOK ;yes, everything went alright->exit movf datawrhi,W ;copy data movwf datawr_c_hi movf datawrlo,W movwf datawr_c_lo movlw 0x10 ;4 commandbits and 12 databits --> 16 bits in total movwf counter goto FrameLP ;Do another frame FrameOK call IntON retlw 0x00 FrameFAIL call IntON retlw 0x01 ;---------------Exit from the ISP mode------------ ExitISP call IntOFF movlw OSC1LOW ;OSC1=low movwf PORTA call SyncISP ;wait for the sync cycle ->SX exits ISP after sync movlw 0x30 ;give the SX some extra time to exit ISP call Delay movlw OSC1FLOAT movwf PORTA ;release osc1 PAGE1 bsf TRISB,OSC2 ;release the osc2 pin PAGE0 call IntON return ;-------synchronize to the SX chip------------------ ;SyncISP synchronize to the SX by waitng for a sync cycle ;returncodes: ; 0x00 OK we are in a sync cycle ; 0x01 NOT ok no sync cycle was found SyncISP movlw 0x40 ;retry's= 64 (about 3-4 frames) movwf counter SyncHigh btfss PORTB,OSC2 ;wait for OSC2 to get high goto SyncHigh movlw 0x12 ;timeout= 18*5= 95 cycles= 39us movwf timer SyncLP btfss PORTB,OSC2 ;now wait for a falling edge goto SyncEdge decfsz timer goto SyncLP retlw 0x00 ;time out -> this is a sync cycle SyncEdge decfsz counter ;we detected an edge ->this was not a sync cycle goto SyncHigh retlw 0x01 ;too many retry's, synchronization failed ;------------------------------------------------- ;-------------system support routines------------- ;------------------------------------------------- SendSerial btfsc flags,send ;Sends byte in W over to the serial port goto SendSerial movwf shiftout movlw 0x0a movwf bitout movwf countout bsf flags,send return GetSerial clrwdt ;!!!! ONLY FOR SX4AMIGA!!!! btfss flags,buf ;Waits for byte and returns byte in W goto GetSerial movf buffer,W bcf flags,buf return IntOFF movf flags,W ;Switch interrupts off andlw 0x03 btfss STATUS,Z ;wait for serial to finish goto IntOFF bcf INTCON,GIE return IntON bcf INTCON,T0IF ;Switch interrupts back on bcf INTCON,INTF bsf INTCON,GIE return Delay addlw 0xff ;Delay for W*4 cycles btfss STATUS,Z goto Delay return ; convert hex value in W to ascii in W HexToAsc andlw 0x0f ;mask out 1 nibble movwf tmp addlw 0xf6 ;greater than 9? btfsc STATUS,C goto HexHigh movf tmp,W ;0-9 addlw 0x30 return HexHigh movf tmp,W ;a-f addlw 0x57 return ; convert ascii in W to hex value in W AscToHex movwf tmp addlw 0xb0 ;greater than 0x50 ? btfsc STATUS,C goto AscHigh movf tmp,W ;0-9 addlw 0xd0 andlw 0x0f return AscHigh movf tmp,W ;a-f addlw 0xa9 andlw 0x0f return ;---------------------Interrupt Handling------------ ;-------------------and RS-232 Interfacing---------- Int_Service movwf Wstack movf STATUS,W movwf Sstack PAGE0 btfss INTCON,T0IF goto Skip movlw Baudrate movwf TMR0 bcf INTCON,T0IF btfsc flags,send call Send btfsc flags,receive call Receive Skip btfsc INTCON,INTE call Startbit swapf Wstack movf Sstack,W movwf STATUS swapf Wstack,W bsf INTCON,GIE return Startbit btfss INTCON,INTF return movlw 0x09 movwf bitin bcf INTCON,INTE bcf INTCON,INTF bsf flags,receive movlw Halfcount movwf countin return Receive decfsz countin return movlw Baudcount movwf countin rrf shiftin bcf shiftin,7 btfsc PORTB,rxd bsf shiftin,7 decfsz bitin return Received bcf flags,receive bcf INTCON,INTF bsf INTCON,INTE movf shiftin,W movwf buffer bsf flags,buf return Send decfsz countout return movlw Baudcount movwf countout movf bitout,W xorlw 0x0a btfss STATUS,Z goto Dataout bcf PORTB,txd decf bitout return Dataout btfsc shiftout,0 bsf PORTB,txd btfss shiftout,0 bcf PORTB,txd bsf STATUS,C rrf shiftout decfsz bitout return bcf flags,send return