Tiny PIC bootloader

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Tiny Bootloader

This is a bootloader for the Microchip PIC microcontrollers.

It is the smallest bootloader, taking less than 100 words of program space;
Supports families of PIC devices: 16F, 18F, dsPIC30 (those devices that support self-programming)
Does not support yet PIC24, dsPIC33, PIC18xxJyy

Download Tiny PIC Bootloader

Features of the firmware

Size of only 100 words; (all versions, for 16F,18F,dsPIC occupy less than 100 words);
Can write flash, eeprom and configuration bytes(18F);
On reset, waits 1 second (adjustable) for a message from the PC, if not received, launch user application;
The .asm file can be easily modified and adapted for any frequency (or baudrate);

Features of the PC software

Can upload programs into flash (in current version eeprom and cfg bytes can be modified only manually, depending on the device type);
Works with PIC16F,PIC18F and dsPIC types; automatically detects HEX content and PIC model;
Remembers last settings;
In case of errors, performs retransmissions or tries to resynchronize with pic;
The communication settings are editable so you can write any COM number or desired baud;
If a filename is specified as a command line parameter, it will automatically try to write it;

How to use TinyBld

Supported/Tested Devices

Device Devices of the same type Flash ram EE ser adc osc pin

PIC 16F Family

PIC16F876 877, 873, 874

PIC16F876A 877A, 873A, 874A 8k .3 .2 1 y dD

PIC16F887 PIC16F886

PIC16F88 87 4k .3 .2 1 y y d

PIC 18F Family

PIC18F252 452, 242, 442; 2420, 2520, 4420, 4520 16k 1.5k .2 1a y dD

PIC18F258 458, 248, 448; 2480, 2580, 4480, 4580 16k 1.5k .2 1a y dD CAN

PIC18F2620 4620, 2525, 4525 32k 3.9k 1k 1e y y dD

PIC18F1320 1220, 2220, 2320 4k .2 .2 1e y y d

PIC18F8720 6520, 8520, 6620, 8620, 6720; 6621 64k 3.8k 1k 2 y Q ext.mem.

PIC18F2550 4550, 2455, 4455 16k 1.5k .2 1e y Y dD usb

PIC18F4431 2331, 2431, 4331 8k .7 .2 1e Y dD advPWM

PIC18F4680 2585,2680,4585 32k 3.3 1k 1 y dD ECAN

PIC18F4580 2480,2580,4480 16k 1.5 .2 1 y dD ECAN

PIC18F4620 2525,2620,4525 32k 3.9 1 1 y dD

PIC18F4320 2220,2320,4220 4k .5 .2 1 y dD

dsPIC Family

Device Devices of the same type Flash ram EE ser adc osc pin

dsPIC20F2010 4k .5 1k 1 y y d 6pwm

dsPIC30F6014 6012, 6013, 6011, 6012A 44k 8k 4k 2 yy y Q 2CAN

dsPIC30F3013 3012, 2012, 2011 8k 2k 1k (2) yy YY d

dsPIC30F4012 4011 16k 2k 1k (2) y Y dD 6pwm, CAN

dsPIC30F3011 3010 8k 1k 1k (2) y Y dD 6pwm

dsPIC30F6010 44k 8k 4k 2 y y Q 8pwm, 2CAN

blue - tested for longer periods
blue - verified (or user source provided)
navy - reported to work (may require modifications!) Flash, RAM, EEprom: max. amount
ser: a=addr.; e=enh.(brg/lin)
adc: yy=12bit
osc: internal+features
pin: d<=dip28; D=dip40; Q>=tqfp

General info about Bootloaders

A bootloader is a program that stays in the microcontroller and communicates with the PC (usually through the serial interface). The bootloader receives a user program from the PC and writes it in the flash memory, then launches this program in execution. Bootloaders can only be used with those microcontrollers that can write their flash memory through software. The bootloader itself must be written into the flash memory with an external programmer. In order for the bootloader to be launched after each reset, a "goto bootloader" instruction must exist somewhere in the first 4 instructions; There are two types of bootloaders, some that require that the user reallocate his code and others that by themselves reallocate the first 4 instructions of the user program to another location and execute them when the bootloader exits.

(Some of the) Available bootloaders (as reported by Google) in May, 2003:

Bootloader Name / Author Supported models Size(words) Comments

From Microchip
16F,18F 1000 uses Hyperterminal to upload hex files

From MicrochipC
16F,16F*A,18F 256/2000 +ok

WLoader
Wouter van Ooijen 16f877 1000 +does not use the UART,
+the serial interface use only one I/O pin

ZPL
Wouter van Ooijen 18F

384 +unusual method using mclr: uses zero I/O pins !

KarlLunt
16f87x 512 -activation on input pin
-derived from Microchip boot877.asm (uses Hyperterminal)

PICLOADER
Rick Farmer PIC16F87x 2000 -program must start at 0x3; +password
(uses Hyperterminal)

bootload
PIC16F877 800 -written in C
-command line DOS program

theByteFactory
16F877 1000 -written in C
(uses Hyperterminal)

Jolt
Martin Dubuc 18F 256 -user code and interrupt vectors need to be relocated;
Java GUI, +auto detect baud

?
HI-TECH Software 16F87x 256 -written in C

PIC downloader
Petr Kolomaznik 16F876 256 -is rewritten and modified from HI-TECH
+Windows interface

Ivar Johnsrud
18Fxx2/18Fxx8 360 -bootloader based on HiTech's
-downloader based on Petr Kolomaznik's

B Bootloader
PIC16F87x, PIC16F87xA 340 -called only by user application
-written in C +Linux uploader

SGupta
16f876 256

I put mine here, for comparison:

Tiny 16F, 18F, dsPIC 100 +details above

This project was born because:

Some bootloaders I used previously had some unpleasant bugs or didn't support the devices I had.
I wanted to do it small.
If you wonder how much smaller than this can it get, the answer is 32words :), but it loses from features, reliability and speed.
TinyBootloader was build with the idea that all the hard work could be moved to the PC application, while the firmware can implement only the basic functions.

Critics and suggestions at:
(Due to mail server spam filters (beyond my control) stopping many good emails, and deleting them after a short period, it is possible to miss some of the messages)