The Toshiba TX19A inside most Canon DSLR Camera is the MPU, which is certainly the I/O manager.


The TX19A (TMP19A43FDXBG, in RED square) on the 50D mainboard.

550D, 600D: TMP19A43CDXBG.

See HV30_Firmware_Analysis#Processor_and_architecture



  • 512K Flash
  • 24K RAM
  • Big endian, 16 and 32 bit ISA, MIPS 16 ASE
  • 18 I/O ports
  • 10-bit ADC
  • 8-bit DAC


Memory MapEdit

  • 0xFFFFE000 - 0xFFFFFFFF: I/O registers (from datasheet)
    • f000 - f08f: I/O ports
    • f090 - f091: watchdog
    • f140 - f23f: 16-bit timer
    • f250 - f25f: i2c/sio
    • f260 - f28f: uart/sio
    • f300 - f31f: 10-bit adc
    • f330 - f33f: 8-bit dac
    • f360 - f38f: key on wake-up circuit
    • f400 - f42f: 32-bit input capture
    • f440 - f47f: 32-bit output compare
    • e000 - e10f: interrupt controller
    • e200 - e37f: dma controller
    • e400 - e49f: cs/wait controller (?)
    • e510 - e52f: flash control
    • e540 - e57f: ROM correction
    • e700 - e71f: clock timer
    • e800 - e84f: uart/hsio
    • ee00 - ee4f: clock generator
  • 0xFFFF8000 - 0xFFFFDFFF: built-in RAM
  • 0x00000000 - 0x0007FFFF: internal ROM? (code executes from here)
  • 0xBFC00000 - 0xBFC7FFFF: internal ROM copy?
  • Note: TX19A only allows using Kernel mode


See TX19A43 features (here) including:

  • High-Speed Multipoint AF
    • High-speed AD converter (for processing analog signals from an AF sensor)
    • High-speed multiply accumulate operation
  • Large Number of External Interrupt Lines
  • Motor Control with Sync Start Control
    • PPG (PWM)
  • High-Speed E2PROM Supported


Strings found in MPU codeEdit

In 550D 1.0.6 update, record #2 (k270_mpu.mot). See Update_records.

First column is offset in hex.

    509 AE_GERO_DATA_T:
    51c [AE]Read Error!
   128b EF-S
   1290 TS-E
   1295 MP-E
   12d5 1200
   12da 10-22
   12e0 16-35
   12e6 17-35
   12ec 17-40
   12f2 17-55
   2860  Switch State Information 
   287b  LockSw                        : 
   289d Lock(Off)
   28a7 UnLock(On)
   28b2  CardCover                     : 
   28d4 Open
   28d9 Close
   28df  BatCover                      : 
   2901  SDDetectSw                    : 
   292a  Sw1                           : 
   294c  Sw2                           : 
   296e  AELockButton                  : 
   2990  SpdnButton                    : 
   29b2  StroboPopUpButton             : 
   29d4  StroboPopEndSw                : 
   29f6  AFFrameSelectButton           : 
   2a18  ISOButton                     : 
   2a3e }Button                    : 
   2a5c  SetButton                     : 
   2a7e  MenuButton                    : 
   2aa0  PlayButton                    : 
   2ac2  EraseButton                   : 
   2ae4  DisplayButton                 : 
   2b06  EasyDirect&QuickSetting       : 
   2b28  RECStartButton                : 
   2b4a  CrossUp                       : 
   2b6c  CrossDown                     : 
   2b8e  CrossRight                    : 
   2bb0  CrossLeft                     : 
   2bd2  ModeDial                      : 
   2bf4 Program
   2c02 Manual
   2c09 A-DEP
   2c0f Green
   2c15 NightPortrait
   301b [MAIN]:popup mech
   302e [MAIN]:popend fault
   3043 [MAIN]:aux popup end
   305a GetJunkBvCountLiveView ERROR
   3078 [MAIN]:<TIMEOUT>lv ae
   308f [MAIN]:<WARNING>illegal iso data
   30b4 [MAIN]:lv started mech
   30cc [MAIN]:lv mirr down
   30e4 [MAIN]:<TIMEOUT>rel event from mech
   3109 [MAIN]:<ERR>(
   311a [MAIN]:<TIMEOUT>popup event from mech
   314c [MAIN]:dcdc-ic current chk err
   316c [MAIN]:dcdc-ic write err
   3186 [MAIN]:dcdc-ic read err [
   31a4 [MAIN]:BC
   31b7 [MAIN]:BC
   31ca [BC PRINT]:Vop -> 
   31dd (raw:
   31e6 [BC PRINT]:Aop -> 
   31f9 [BC PRINT]:Vbc -> 
   320c [BC PRINT]:Abc -> 
   321f [BC PRINT]:Vfo1 -> 
   3235 [BC PRINT]:Vfo2 -> 
   3249 [BC PRINT]:VfoSt -> 
   325e [BC PRINT]:R -> 
   3270 [MAIN]:<TIMEOUT>mech restore
   4038 DUMPB
   403e DUMPW
   4044 DUMPL
   40ee   MPU Ver...0x
   40fd   MPU code   area check sum...0x
   4126  LgSelSw                       : 
   414f  BatSelSw0                     : 
   4171  BatSelSw1                     : 
   4196 Too Long!
   41a6 SERVO
   41b6 parameter err
   41c6 ---power info---
   41d8 bat kind
   41e3 (Grip)
   41ea level
   41f2 vbat(noload)
   4201 vbat(bcon)
   420e mech pwm
   4219 tchk ad
   4230 ---temperature info---
   4248 aeic
   424f efic
   4256 Atemp(
   4261 AtempAD:
   426a LVTIME:
   4272 MovieTime:
   4415 MON>>
   4420 E1ON
   4425 MON>>
   442c E1OFF
   4447 T-----------------------------------------------------------
   4484                K270 Debug Monitor (Ver 1.00)               
   44c0      Copyright(C) CANON INC. 2007  All Rights Reserved.    
   44fc -----------------------------------------------------------
  1d52c MDUMP
  1d552 .QMDUMPB
  1d57a .QMDUMPW
  1d5a2 .QMDUMPL
  1d5ca .QMMOT
  1d5f2 1)FCBDUMP
  1d61c FCBR
  1d644 FCBW
  1d694 TITLE
  1d6bc ABOUT
  1d734 S00F00006B3237305F6565702E6D6F74D5
  1d75a E-S00F00006B3237305F6565702E6D6F74D5
  1d782 BQEEPR
  1d7ac EEPW
  1d7d2 BQMLOAD
  1d7fa E-MRESET
  1d822 FQEXEC
  1d84a :ESW
  1d872 3yON
  1d912 4eDISPBLINK
  1d93a 4uDISPTEST
  1d98c TESTEL
  1d9dc TESTFLED
  1da2c TESTSI
  1da7a 7!TESTPWROFF
  1daa4 BCINFO
  1dacc BATKIND
  1daf4 TEMPINFO
  1db1a 9-PRINTLEVEL
  1db44 UPBNY
  1db6a P5SENDICU


Requirements to disassemble TX19a code:

  • IDA Pro 6.2 with MIPS support + TX19A plug-in (Done by JollyRogerXP from CHDK forum)
  • IDA Pro 6.3 with TX19A support

to compile JollyRogerXP's plug-in use this documentation: and settings in section 3.1


  1. chooses MIPS big endian processor
  2. loading address is 0xffff8000 for file k250_mpu.mot_ffff8000.bin, for example
  3. activate the tx19A plug-in
  4. Alt-G to set the MIPS16 virtual register to 1
  5. Hit C for Code

it looks like this

ROM:FFFF8000  # Processor       : mipsb
ROM:FFFF8000  # Target assembler: GNU assembler
ROM:FFFF8000  # Byte sex        : Big endian
ROM:FFFF8000 .set noreorder
ROM:FFFF8000 .set noat
ROM:FFFF8000  # ===========================================================================
ROM:FFFF8000  # Segment type: Pure code
ROM:FFFF8000                 .text # ROM
ROM:FFFF8000                 .set mips16
ROM:FFFF8000                 save    0x10
ROM:FFFF8004                 mov32r  $s1, $a1
ROM:FFFF8006                 mov32r  $s2, $a2
ROM:FFFF8008                 lui     $a2, 0
ROM:FFFF800C                 addiu8  $a2, 0x8E88
ROM:FFFF8010                 lw      $a1, 0($a2)
ROM:FFFF8012                 li      $v0, 0xFF
ROM:FFFF8014                 sb      $v0, 0($a1)
ROM:FFFF8016                 li      $v0, 0x80
ROM:FFFF8018                 and     $v0, $a0
ROM:FFFF801A                 bnez    $v0, loc_FFFF8020
ROM:FFFF801C                 li      $v0, 0
ROM:FFFF801E                 sb      $v0, 0($a1)
ROM:FFFF8020 loc_FFFF8020:

See also: SIO3_MREQ, Update_records, Datasheets

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