Bootloader of 84 words

[Dan]

Hi,All,

I introduce it because we succeeded in developing a 84 word firmware in PIC10F322.

[Way of thinking]
1 second loop using cnt1, cnt2, cnt3 the Receive routine requires a lot of code.
To shorten the code using the WDT (2 seconds initial).

[Before]
IntrareBootloader:
clrf ANSELA ; digital I/O
#ifdef Direct_TX
bcf LATA,TX
#else
bsf LATA,TX
#endif
bcf TRISA,TX ; set TX Port
call Receive ; init int clock & serial port
; wait for computer
sublw 0xC1 ; Expect C1
skpz
goto way_to_exit ; connection errer or timeout

Receive: movlw xtal/2000000+1 ; for 20MHz => 11 => 1second
movwf cnt1
rpt2: clrf cnt2
rpt3: clrf cnt3
rptc: ; check Start bit
#ifdef Direct_RX
btfss PORTA,RX
#else
btfsc PORTA,RX
#endif
goto $+4
call r1rx11 ; recive data
addwf crc,f ; compute checksum
return

            decfsz  cnt3,f
            goto    rptc
            decfsz  cnt2,f
            goto    rpt3
            decfsz  cnt1,f
            goto    rpt2

way_to_exit: goto first_address ; timeout:exit in all other cases

[After]
IntrareBootloader:
btfss STATUS,NOT_TO
goto first_address ; connection errer or timeout

    clrf    ANSELA          ; digital I/O

#ifdef Direct_TX
bcf LATA,TX
#else
bsf LATA,TX
#endif
bcf TRISA,TX ; set TX Port
call Receive ; init int clock & serial port
; wait for computer
sublw 0xC1 ; Expect C1
skpz
goto first_address ; connection errer or timeout

Receive: bsf WDTCON,SWDTEN ; start WDT(2s)

    #ifdef  Direct_RX
            btfss   PORTA,RX
    #else
            btfsc   PORTA,RX
    #endif
            goto    $-1

            bcf WDTCON,SWDTEN   ; stop WDT and clear
    call    r1rx11          ; recive data
            addwf   crc,f           ; compute checksum
            return

[Dan]

Adding.

I was able PIC12F1822, PIC16F1823 also fit into 84 words.

Although I checked the writing of EEPROM,
It will fail if attempted to write EEPROM in V0.8.0 or later.

I made sure to write the EEPROM in V0.7.1.

Changes in V0.7.1

①Change of source
B --> K

②Add to piccodes.ini
$19, B, 12F 1822(84W), $1000, 256, 168, 32,
$37, B, 16F 1823(84W), $1000, 256, 168, 32,

[Dan]

Hi,ALL,

It is a bootloader for ATTINY13A/84Words.

The addition of a slight modification,
applicable to the following ATTINY.

ATTINY24A
ATTINY25
ATTINY261A

[Dan]

Hi,ALL,

There was a small bug in the firmware of PIC16F1823 and PIC12F1822.

[Contents of the bug]
It rewrite the 01Dh without rewriting the RCSTA (19Dh) to WDT reset after detection.

I will up the bug fix products.

[Change]
RCSTA because it is cleared by WDT reset,
I have changed the jump destination of the WDT reset after detection.

There is no effect on the operation even if there is a bug,
because it has not yet been implemented 01Dh

[Dan]

Hi,All,

There was a bug in the firmware of ATTINY13A.
(This does not affect the behavior.)

[Contents of the bug]
Code jump to the bootloader is wrong.

            .org    0x0000      ;;Reset vector

; RJMP IntrareBootloader
.dw 0xcf9f ;RJMP PC-0x60

-------------------------->

            .org    0x0000      ;;Reset vector

; RJMP IntrareBootloader
.dw 0xcfaf ;RJMP PC-0x50

I attach the modified version.

[edorul]

Hello Dan!

Thanks for these firmwares :-)
I'll put them in the next release of TinyBootloader+

Best regards,
Edorul

[Ayinde Olayiwola]

Hi Dan, i have been trying for months on increasing the TinyBootloader size from 100words to about 200words for PIC18, what do i need to change in the code and PC Software?

[Anobium]

Why? The bootloader is intended to be less that 100words - why increase?

Please explain rational for the ask.

[Ayinde Olayiwola]

Thank you Anobium for the reply,

My Tiny Bootloader software will show "Error: hex file too large, writing bootloader firmware" error message when uploading if code is more than 2000h of the program memory space.