Canon A570 IS 1.01A firmware dumped

November 11, 2007 1:20 am UTC | In Tech

Today I dumped Canon PowerShot A570 IS 1.01A firmware using tricks from CHDK website. Here’s a little bit tech detail for my own record.

  • Receiver: Thorlabs DET110 + 10k terminating resistor.
  • Recording: 48 kHz sampling, 8 Bit, Mono. Delay settings I used:
    #define DELAY_SYNC   200
    #define DELAY_SPACE  50
    #define DELAY0       50
    #define DELAY1       100

    I slowed down the blinking to make my sound card happy. However, the following faster setting:

    #define DELAY_SYNC   45
    #define DELAY_SPACE  50
    #define DELAY0       1
    #define DELAY1       25

    does give very clean waveform (even with the shortest 5 us pulse) on the scope, so it should work with good sampling device (say a better sound card).

  • LED: I used the least-frequently-used blue LED
    #define LED_BLUE 0xc02200c4
  • Recording level set at about -5dB to -3dB
  • Decoder setting:
    #define LEVEL_THRES_HI  0xa0
    #define LEVEL_THRES_LO  0x80
    
    #define LEN_SYNC        10
    #define LEN_SPACE       1
    #define LEN_0           3
    #define LEN_1           6
  • Total dump time is about 2.5 hours. (about 3700 bits per second)
  • I did not have any CRC error! I added an md5 checksum at the end. The camera took about 17 seconds to calculate md5sum of the 4MB firmware. Of course, no surprise, md5sum matches.
  • Starting part of the dump:
    dump start
    Decoded as 00110000, 00110001, 00110010, in other words, ASCII ’0′, ’1′, ’2′. Also, for some reason the waveform is inverted (compared with CHDK website), so I have to manually invert the waveform for adc.
  • The camera freezes about 3 milliseconds every few seconds. Here’s typical behavior:
    dump delay
    Since the protocol is decently robust, this extra delay is not a problem at all.
  • Dumper code available for download: a570is dumper (based on code from CHDK website and kxn’s modification.).

Brilliant kxn ported CHDK to A570 IS 1.01A within two days.

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2 Comments

  1. Quick question for you – do you know if 1.01a is the latest fw? When did you buy the camera?

    This is the cheapest CHDK-compatible camera that you can still purchase new from just about everywhere. I’m actually planning to buy it based on your excellent work!

    Comment by bob — November 24, 2007 6:27 pm UTC #

  2. I bought it in Aug 2007 for my lab. As far as I know, 1.01a is the latest fw. Yeah it’s a good camera, I am planning to buy one for my own.

    Comment by atppp — November 24, 2007 7:25 pm UTC #

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