Mecanique's internal bootloader OSC

[SUNFLOWER]

I know this concerns meLabs. Once compiled mass production begins. So meLabs only get paid per software development workstation, not per dish. That is the future. For now, multiple startups will require PBP for developing their proprietary Dish_Operating_System.hex. Our kernel DOS is open source as a starting point. We have bigger fish to fry.

[SUNFLOWER]

MicroChip Bootloader P1618QP.EXE and Tiny_Loader both have the same conflict with internal oscillators and bootloaders.

Anyway, I think I need help to jump past bootload space, set one bit OSCCON.5 = 1, then jump to the start of bootload and program at 4 MHz. I would be forever grateful.

[prstein]

For what it's worth, I've had good success with Mechanique in politely asking for "special" loader hex files. Mine were for the 18F1220 and 18F1320 using the internal oscillator at 4 and 8 MHz (so a total of 4 files). That was a few years ago.

So have you emailed Mechanique and asked? I really don't think it's a huge deal on their part.

Best Regards,
Paul

[Charles Linquis]

I assume posting code would violate some sort of copyright, but I have modified MCLOADER to do all sorts of different things.

If you are brave, you can dissassemble the .HEX file and look for where it sets up the USART Change those (probably two) 'movlw' lines and re-assemble.

Open MPLAB, import the .HEX file and choose VIEW MEMORY. Although there is probably an easier way, I set up a "send print to file" printer and chose <CTRL><P> to save the dissasembly as txt.

Use a DIFF program (I use ARAXIS) to compare the 20MHz and the 4MHz bootloaders. The rest is easy.

[SUNFLOWER]

Thanks Charles. If I had fear I would not be here. I did not know what a PIC was two weeks ago.

I had engineers before the economy went into a coma. My skill set will not assemble and am at the mercy of strangers.

Yes, prstine, I saw (your?) post from years ago and wrote Mechanique. I am surprised this problem persists. I am old enough to remember using slide rules in physics class. Friends were flipping switches on the Altair while I was using the mainframe to design geodesic dishes. It was then that I heard, "Time is mother nature's way of preventing everything from happening at once". So I hope in good time these loaders will become more flexible.

Thanks for all the responses.

Best,
Doug

[Charles Linquis]

If it is useful for you, you can modify the bootloader after it is installed. Your program can erase FLASH (with the ERASECODE) instruction.

You have to look at the erase block size for your chip (probably 64 bytes), and (in this case) start on a 64 byte boundary. That will erase 64 sequential bytes. Then you write back the new data with the WRITECODE instruction. The WRITE block size may or may not be the same size as the ERASE block size.


I had a customer who felt that the bootloader was a security breach, and wanted to run it only when a jumper was installed. The boards were installed and couldn't be returned. I had very few free pins.

My code wrote to the CONFIG register and turned MCLR into an in input, then it read and changed the jump vector at location 0 to a point in memory ABOVE MCLoader. There, I had a routine that checked for the the MCLR line to be low, if it was, I jumped to the MCLOADER entry point, if not, I jumped back to my program and bypassed the bootloader.

I know this isn't a forum for "war stories" but my wife and friends don't understand any of this!

[ScaleRobotics]

MicroChip Bootloader P1618QP.EXE and Tiny_Loader both have the same conflict with internal oscillators and bootloaders.

Yes they do. But with Tiny Bootloader, they give you the source code, so you can change anything you want. Although, Charles has me interested about disassembling the MCLoader files! Thanks Charles, I will try that!

Here is a modified Tiny Bootloader. Untested, but here are the changes I made.

    radix DEC
    LIST      P=18F4620    ; change also: Configure->SelectDevice from Mplab 
xtal EQU 4000000        ; set for 4 mhz you may want to change: _XT_OSC_1H  _HS_OSC_1H  _HSPLL_OSC_1H
baud EQU 9600            ; the desired baud rate
    ; The above 3 lines can be changed and buid a bootloader for the desired frequency (and PIC type)
    
    ;********************************************************************
    ;    Tiny Bootloader        18F series        Size=100words
    ;    [email protected]
    ;    http://www.etc.ugal.ro/cchiculita/software/picbootloader.htm
    ;********************************************************************
    

    #include "icdpictypes.inc"    ;takes care of: #include "p18fxxx.inc",  max_flash, IdTypePIC
    #include "spbrgselect.inc"    ; RoundResult and baud_rate

        #define first_address max_flash-200        ;100 words
    __CONFIG _CONFIG1H, _OSC_INTIO67_1H & _FCMEN_OFF_1H & _IESO_OFF_1H 
    __CONFIG _CONFIG2L, _PWRT_OFF_2L & _BOREN_OFF_2L 
    __CONFIG _CONFIG2H, _WDT_OFF_2H & _WDTPS_1_2H 
    __CONFIG _CONFIG3H, _MCLRE_ON_3H & _PBADEN_OFF_3H & _CCP2MX_PORTBE_3H 
    __CONFIG _CONFIG4L, _DEBUG_OFF_4L & _LVP_OFF_4L & _STVREN_OFF_4L & _XINST_OFF_4L
    __CONFIG _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L & _CP2_OFF_5L
    __CONFIG _CONFIG5H, _CPB_OFF_5H 
    __CONFIG _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L & _WRT2_OFF_6L
    __CONFIG _CONFIG6H, _WRTB_OFF_6H & _WRTC_OFF_6H
    __CONFIG _CONFIG7L, _EBTR0_OFF_7L & _EBTR1_OFF_7L & _EBTR2_OFF_7L
    __CONFIG _CONFIG7H, _EBTRB_OFF_7H & _DEVID1 & _IDLOC0


;----------------------------- PROGRAM ---------------------------------
    cblock 0
    crc
    i
    cnt1
    cnt2
    cnt3
    counter_hi
    counter_lo
    flag
    endc
    cblock 10
    buffer:64
    endc
    
SendL macro car
    movlw car
    movwf TXREG
    endm
    
;0000000000000000000000000 RESET 00000000000000000000000000

        ORG     0x0000
        GOTO    IntrareBootloader

;view with TabSize=4
;&&&&&&&&&&&&&&&&&&&&&&&   START     &&&&&&&&&&&&&&&&&&&&&&
;----------------------  Bootloader  ----------------------
;PC_flash:        C1h                U        H        L        x  ...  <64 bytes>   ...  crc    
;PC_eeprom:        C1h                   40h   EEADR   EEDATA    0        crc                    
;PC_cfg            C1h            U OR 80h    H        L        1        byte    crc
;PIC_response:       type `K`
    
    ORG first_address        ;space to deposit first 4 instr. of user prog.
    nop
    nop
    nop
    nop
    org first_address+8
IntrareBootloader
                            ;init serial port
    movlw b'00100100'
    movwf TXSTA
    movlw spbrg_value
    movwf SPBRG
    movlw b'10010000'
    movwf RCSTA

    movlw b'01100000'        ;ADDED to set osccon to 4mhz internal
    movwf OSCCON 
                            ;wait for computer
    rcall Receive            
    sublw 0xC1                ;Expect C1h
    bnz way_to_exit
    SendL IdTypePIC            ;send PIC type
MainLoop
    SendL 'K'                ; "-Everything OK, ready and waiting."
mainl
    clrf crc
    rcall Receive            ;Upper
    movwf TBLPTRU
        movwf flag            ;(for EEPROM and CFG cases)
    rcall Receive            ;Hi
    movwf TBLPTRH
        movwf EEADR            ;(for EEPROM case)
    rcall Receive            ;Lo
    movwf TBLPTRL
        movwf EEDATA        ;(for EEPROM case)

    rcall Receive            ;count
    movwf i
    incf i
    lfsr FSR0, (buffer-1)
rcvoct                        ;read 64+1 bytes
        movwf TABLAT        ;prepare for cfg; => store byte before crc
    rcall Receive
    movwf PREINC0
    decfsz i
    bra rcvoct
    
    tstfsz crc                ;check crc
    bra ziieroare
        btfss flag,6        ;is EEPROM data?
        bra noeeprom
        movlw b'00000100'    ;Setup eeprom
        rcall Write
        bra waitwre
noeeprom
        btfss flag,7        ;is CFG data?
        bra noconfig
        tblwt*                ;write TABLAT(byte before crc) to TBLPTR***
        movlw b'11000100'    ;Setup cfg
        rcall Write
        bra waitwre
noconfig
                            ;write
eraseloop
    movlw    b'10010100'        ; Setup erase
    rcall Write
    TBLRD*-                    ; point to adr-1
    
writebigloop    
    movlw 8                    ; 8groups
    movwf counter_hi
    lfsr FSR0,buffer
writesloop
    movlw 8                    ; 8bytes = 4instr
    movwf counter_lo
writebyte
    movf POSTINC0,w            ; put 1 byte
    movwf TABLAT
    tblwt+*
    decfsz counter_lo
    bra writebyte
    
    movlw    b'10000100'        ; Setup writes
    rcall Write
    decfsz counter_hi
    bra writesloop
waitwre    
    ;btfsc EECON1,WR        ;for eeprom writes (wait to finish write)
    ;bra waitwre            ;no need: round trip time with PC bigger than 4ms
    
    bcf EECON1,WREN            ;disable writes
    bra MainLoop
    
ziieroare                    ;CRC failed
    SendL 'N'
    bra mainl
      
;******** procedures ******************

Write
    movwf EECON1
    movlw 0x55
    movwf EECON2
    movlw 0xAA
    movwf EECON2
    bsf EECON1,WR            ;WRITE
    nop
    ;nop
    return


Receive
    movlw xtal/2000000+1    ; for 20MHz => 11 => 1second delay
    movwf cnt1
rpt2                        
    clrf cnt2
rpt3
    clrf cnt3
rptc
        btfss PIR1,RCIF            ;test RX
        bra notrcv
        movf RCREG,w            ;return read data in W
        addwf crc,f                ;compute crc
        return
notrcv
    decfsz cnt3
    bra rptc
    decfsz cnt2
    bra rpt3
    decfsz cnt1
    bra rpt2
    ;timeout:
way_to_exit
    bcf    RCSTA,    SPEN            ; deactivate UART
    bra first_address
;*************************************************************
; After reset
; Do not expect the memory to be zero,
; Do not expect registers to be initialised like in catalog.

            END

[SUNFLOWER]

Thanks scalerobotics. It worked crystal clear... only once. After that Tiny_bootloader could not find PIC unless it was totally erased, Tiny bootloader reloaded, then Tiny found PIC and Tiny programmed PIC, only once, then round we go again. So there is a conflict somewhere in the fog...

Best,
Doug

[Bruce]

It must be dirt cheap

If you're not using a crystal just to keep costs down, why not get rid of the MAX IC, DB-9 connector, supporting caps, and just design-in a 5-pin header for in-circuit programming?

The PGD and PGC pins could be used for serial communications if you need to monitor what's happening on the board.

If this board will be installed outdoors, you're most likely going to have issues when attempting to boot-load new firmware anyhow due to changes in temperature. The internal osc is fine when indoors, but when exposed to extreme temp changes it will drift considerably, and you will have major problems just trying to load new firmware.

You won't have that problem with in-circuit programming. A Pickit2 could be used for firmware updates & as the serial monitor if needed, and a Pickit2 costs even less than MCS+.

Your board is a lot less expensive, and your programming tool is less expensive + more reliable, and you can use any internal osc speed you prefer.