Personal Projects Log

• Mar 25, 2019

  Rockwell Automation Presentation Events Notes

  I attended a day presentation where they showed some interesting development in the field of Industrial Automation. They are really pushing for integrating factories into the internet via the internet to enable new data analytic opportunities. Here is a few quick notes I made of some of the key interesting things I noted on the day.

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• Oct 7, 2017

  gameboy printer emulation via arduino

  A while ago, I went online and purchased a couple of old gameboy camera carts, I found that it had a bunch of old images taken by the previous owner. Got me thinking that we really should try to save all these images. Thus to assist with this, I written a way to extract images from these old cameras, that can be done on the cheap via an arduino, a link cable and a PC.

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• Sep 30, 2017

  Tips On Testing From Electronex

  During electronex, I’ve made some notes on good designs shown below. These are good tips in general to keep in mind.:

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• Oct 27, 2015

  Cheap Ebay BLE Tag Teardown (iTag via iTracing app)

  Scored really cheap from ebay. Wonder whats inside, and if it can be reprogrammed at all?

  

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• Jul 11, 2015

  V2.0 AVR Convenient Register Macros for digital pins (for at least atmega family)

  Ninja edit: I probbly should reworded with a name that properly specifies that this is mostly useful for manipulating digital pins only.

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• Jul 5, 2015

  understanding more about AVR Programming

  This is just a note for me to recall on how or what really happens in coding an AVR program:

  ATMEL STUDIO 6 Observation

  
  x= register letter (e.g. DDRA DDRB etc... )
  
  DDRx :~ Data Direction Register (read/write)
      : Defines if pin is output=1 or input=0
  
  PORTx :~ Pin Output Mode Register (read/write)
      : If input then
         - pullup=1 floating=0
      : If output then
         - high=1 low=0
  
  PINx :~ Pin INput register (read only)
      : sense @ pin: 1=highIn 0=lowIn
  
  

  How are port registers location defined? e.g. What does PORTD refer to?

  In atmel studio 6 in this location:

  C:\Program Files (x86)\Atmel\Atmel Toolchain\AVR Assembler\Native\2.1.1175\avrassembler\include

  You have an entry in file m328def.inc like:

  
  ...
  .equ	PORTD	= 0x0b
  .equ	DDRD	= 0x0a
  .equ	PIND	= 0x09
  .equ	PORTC	= 0x08
  .equ	DDRC	= 0x07
  .equ	PINC	= 0x06
  .equ	PORTB	= 0x05
  .equ	DDRB	= 0x04
  .equ	PINB	= 0x03
  ...
  
  

  Which defines the IO register pointers in AVR memory.

  ---

  What the hell is .equ ?

  ALSO: http://www.atmel.com/webdoc/avrassembler/avrassembler.wb_directives.html

  Assembler Directives

  All assembler directives have names that begin with a period (`.’). The rest of the name is letters, usually in lower case.

  .equ symbol = expression

  The EQU directive assigns a value to a label. This label can then be used in later expressions. A label assigned to a value by the EQU directive is a constant and can not be changed or redefined.

  Very similar to #define, but can only be defined once.

  Seems to be similar to : http://tigcc.ticalc.org/doc/gnuasm.html#SEC86

  But I think the AVR assembler is a modified version of GCC to accept .equ symbol = expression instead/inaddition? to .equ symbol, expression (Maybe someone can clarify this?)

  ---

  API :~ application programming interfaces define interfaces between program

  ABI :~ application binary interface (ABI) is the interface between two program modules

  ---

  included in avr/io.h ?

  Btw Whats in ‘ #include <avr/io.h> ‘ ? Ans: The compiler and the IDE will include in this location, the officially atmel recognized definition e.g.”avr/iom328p.h - definitions for ATmega328P”

  /* $Id: iom328p.h 2444 2014-08-11 22:10:47Z joerg_wunsch $ */
  
  /* avr/iom328p.h - definitions for ATmega328P. */
  
  /* This file should only be included from <avr/io.h>, never directly. */
  
  #ifndef _AVR_IO_H_
  #  error "Include <avr/io.h> instead of this file."
  #endif
  
  #ifndef _AVR_IOXXX_H_
  #  define _AVR_IOXXX_H_ "iom328p.h"
  #else
  #  error "Attempt to include more than one <avr/ioXXX.h> file."
  #endif
  
  
  #ifndef _AVR_IOM328P_H_
  #define _AVR_IOM328P_H_ 1
  
  /* Registers and associated bit numbers */
  
  #define PINB _SFR_IO8(0x03)
  #define PINB0 0
  #define PINB1 1
  #define PINB2 2
  #define PINB3 3
  #define PINB4 4
  #define PINB5 5
  #define PINB6 6
  #define PINB7 7
  
  #define DDRB _SFR_IO8(0x04)
  #define DDB0 0
  #define DDB1 1
  #define DDB2 2
  #define DDB3 3
  
  etc...
  
  

  ---

  ---

  Arduino Observation

  I see the above is probbly just for AVR Studio with their AVR Assembler.

  For arduino, their source code is a bit different in terms of how it references ports in a chip, using AVR-GCC.

  e.g. You find that in:

  C:\Program Files (x86)\Arduino\hardware\tools\avr\avr\include\avr

  They would define a memmory mapped register as:

  
  #ifndef _AVR_ATmega32U6_H_
  #define _AVR_ATmega32U6_H_ 1
  
  
  /* Registers and associated bit numbers. */
  
  #define PINA _SFR_IO8(0x00)
  #define PINA0 0
  #define PINA1 1
  #define PINA2 2
  #define PINA3 3
  #define PINA4 4
  #define PINA5 5
  #define PINA6 6
  #define PINA7 7
  
  #define DDRA _SFR_IO8(0x01)
  #define DDA0 0
  #define DDA1 1
  #define DDA2 2
  #define DDA3 3
  #define DDA4 4
  #define DDA5 5
  #define DDA6 6
  #define DDA7 7
  
  

  using this cryptic _SFR_IO8 function. But actually, it is not a function, it is a directive.

  As shown in

  http://garretlab.web.fc2.com/en/arduino/inside/avr/sfr_defs.h/_SFR_IO8.html

  Abstract

  The _SFR_IO8() converts the I/O address to the memory address. It is a macro that returns a byte of data at an address of io_addr + __SFR_OFFSET.

  Source Code

  The _SFR_IO8() is defined in hardware/tools/avr/avr/include/avr/sfr_defs.h as below.

  #define _SFR_IO8(io_addr) _MMIO_BYTE((io_addr) + __SFR_OFFSET)
  #define __SFR_OFFSET 0x20
  Adding __SFR_OFFSET to io_addr, then calls _MMIO_BYTE().
  

  Note:

  The use of io_addr + __SFR_OFFSET makes more sense when you see this link http://www.protostack.com/blog/2010/12/avr-memory-architecture/

  The memmory stucture of AVR is like this

  
  # FLASH (16 Bits wide) (start at 0x000, ends at FLASHEND )
   * Application 
    - Flash section ( Read while Write )
    - Optional Flash Section (No Read while Write)
   * Optional Bootloader
  
  # Ram (8bit wide)
   0x0000 : 32 General Purpose Registers
   0x0020 : 64 I/O Registers ( THIS IS WHAT __SFR_OFFSET refers to ) 
             <---- (AKA THIS IS THE SPECIAL FUNCTION REGISTER!)
   0x0060 : 160 Extended I/O Registers
   0x0100 : Internal Ram (Accessable for variables etc...)
   RAMEND : End of internal Ram
   RAMEND+1: External RAM
   0xFFFF : Max memmory address.
  
  # EEPROM ( 8 bit wide) ( start at 0x000, ends at EEPROMEND )
  
  

  So that should give you an idea, of what exactly is going on… At least for AVR-GCC (and AVR Assembler too)

  ---

  • http://gcc.gnu.org/wiki/avr-gcc

  • http://stackoverflow.com/questions/23457389/avr-assembler-define-vs-equ-is-it-the-same

  • http://www.atmel.com/Images/doc1022.pdf - AVR Assembler User Guide (By Atmel)

  • http://www.atmel.com/Images/avr_3_04.pdf

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• Feb 28, 2015

  OpenPGP Card V2.0 Factory Reset

  Had quite a close call with bricking my OpenPGP card which is specifically V2.0 .

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• Feb 24, 2015

  gpg+gpa and a openpgp smartcard

  This is an ongoing log of setting up, installing and then using an open sourced privacy suite.

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• Feb 24, 2015

  cheap quadrocopter toy

  Just recently got my hands on a really tiny quadrocopter. It’s very cool, especially how they managed to get everything to such a tiny form factor. This is no doubt in part of using the PCBs as part of the support structure.

  This wouldn’t be possible without MEMS technologies that you find in a smart phone like accelerometers and gyroscope, in miniaturising components that use to be rather bulky and expensive to use.

  The major ICs onboards are:

  ---

  Microcontroller

  It’s expected it would use a more beefy ARM processor than something like an AVR, since it is doing a closed loop feedback (PID?) control of 4 motors at the same time.

  IC Markings

  MINI54ZAN
  415AC
  2412B048
  -ZZ   _ARM_
  

  Datasheets

  http://www.digikey.com.au/product-detail/en/MINI54ZAN/MINI54ZAN-ND/2786710

  http://media.digikey.com/pdf/Data%20Sheets/Nuvoton%20PDFs/Mini51_Br.pdf

  
  + Core
   - ARM Cortex-M0 core runs up to 50 MHz
   - One 24-bit system timer
   - Support low power sleep mode
   - Single-cycle 32-bit hardware multiplier
   - NVIC for the 32 interrupt inputs, each with 4-levels of priority
   - Support Serial Wire Debug (SWD) interface and 2 watchpoints/4 breakpoints
  + Memory
   - 32K/64K/128K bytes flash memory for program memory
   (APROM) (128K bytes supports NUC100 Medium Density only)
   - 4K bytes flash memory for loader memory (LDROM)
   - Configurable data flash address and size for 128K bytes system,
   fixed 4K bytes data flash (DataFlash) for the 32K bytes and 64K bytes system
   - 4K/8K/16K bytes embedded SRAM (16K bytes supports NUC100
   Medium Density only)
   - Support PDMA mode
  + Clock Control
   - Flexible selection from different clock sources
   - Build-in 22.1184 MHz high speed oscillator (trimmed to 1%) for
   system operation, and low power 10 KHz low speed oscillator
   for Watchdog timer and Wake-up operation
   - Support one PLL, up to 50 MHz, for high performance system operation
   - External 4 ~ 24 MHz high speed crystal input for precise timing operation
   - External 32.768 KHz low speed crystal input for RTC function
   and low power system operation
  + Timers
   - Support 4 sets of 32-bit timers with 24-bit up-timer and one 8-bit pre-scale counter
   - Independent clock source for each timer
   - Provide one-shot, periodic, toggle and continuous counting
   operation modes (NUC100 Medium Density supports one-shot and periodic mode only)
   - Support event counting function (NUC100 Low Density only)
  + PWM
   - Built-in up to four 16-bit PWM generators provide eight PWM
   outputs or four complementary paired PWM outputs
   - Each PWM generator equipped with one clock source selector,
   one clock divider, one 8-bit pre-scale and one Dead-Zone
   generator for complementary paired PWM
   - Up to eight 16-bit digital capture timers (shared with PWM
   timers) provide eight rising/falling capture inputs
   - Support capture interrupt
  + ADC
   - 12-bit SAR ADC with 600K SPS
   - Up to 8-ch single-end input or 4-ch differential input
   - Single scan/single cycle scan/continuous scan
   - Each channel with individual result register
   - Scan on enabled channels
   - Threshold voltage detection
   - Conversion start by software programming or external input
   - Support PDMA mode
  + Communication Interface
   - Maximum 3 UARTs, up to 1 Mbit/s with flow control
   - Maximum 4 SPIs, up to 16 MHz (Master@5V), 10 MHz (Salve)
   - 2 I2Cs
   - Support IrDA (SIR) function
   - Support RS485
  + I2S
   - Interface with external audio CODEC
   - Operate as either master or slave mode
   - Capable of handling 8-, 16-, 24- and 32-bit word sizes
   - Support mono and stereo audio data
  + Analog Comparator
   - Up to two analog comparators
   - External input or internal bandgap voltage selectable at
   negative node
   - Interrupt when compare result change
  + RTC
   - Support software compensation by setting frequency compensate register (FCR)
   - Support RTC counter (second, minute, hour) and calendar counter (day, month, year)
   - Support alarm registers (second, minute, hour, day, month, year)
  + EBI Bus (External bus interface supports NUC100 Low Density 64-pin package only)
   - Accessible space: 64K bytes in 8-bit mode or 128K bytes in 16-bit mode
   - Support 8-/16-bit data width
   - Support byte write in 16-bit data width mode
  + Brownout Detector
   - With 4 levels: 4.5V / 3.8V / 2.7V / 2.2V
   - Support brownout interrupt and reset option
  + GPIOs
   - Up to 80 general-purpose I/O (GPIO) pins
   - Four I/O modes: Quasi bi-direction, Push-Pull output, Open-Drain output, Input only with high impendence
   - TTL/Schmitt trigger input selectable
   - All GPIO pins can be configured as interrupt source with
   edge/level setting
  + Built-in LDO for Wide Operating Voltage Range
   - 2.5V to 5.5V
  + Operating Temperature
   - - 40oC ~ 85oC
  + Packages (RoHS)
   - LQFP48 (7x7mm)
   - LQFP64 (10x10mm)
  
  

  ---

  Motion Processing Unit

  I recognize this! It’s an invensense MPU 6050! A 6 axis MPU (3 axis accerometer + 3 axis gyro)

  IC Markings

  INVENSENSE
  MPU-6050C
  D36138-B1
  EL 1411 E
  

  Datasheet

  http://www.invensense.com/mems/gyro/documents/PS-MPU-6000A-00v3.4.pdf

  ---

  Radio Chip

  This appears to be a radio chip, due to it’s proximity to the antenna

  IC Markings

  BEKEN
  BK2423
  B54144C
  

  Datasheet found:

  http://www.inhaos.com/uploadfile/otherpic/BK2423%20Datasheet%20v2.0.pdf

  BEKEN BK2423:
  
  
  Low Power High Performance 2.4 GHz GFSK Transceiver 
  
  
  2400-2483.5 MHz ISM band operation:
  ? Support 250Kbps, 1Mbps and 2 Mbps air data rate
  ? Programmable output power
  ? Low power consumption
  ? Tolerate +/- 60ppm 16 MHz crystal
  ? Variable payload length from 1 to 32bytes
  ? Automatic packet processing
  ? 6 data pipes for 1:6 star networks
  ? 1.9V to 3.6V power supply
  ? 4-pin SPI interface with maximum 8 MHz clock rate
  ? Compact 20-pin 3x3 or 4x4mm QFN package 
  
  

  ---

  Well?

  What would be interesting, is if the quadrocopter can be reprogrammed to add other motions besides the 360 flip in one of it’s auto acrobatic stunts button (one press and it does a flip in air).

  Either way, it shows how far we have come since the first toy helicopters a few years ago (2015)

  BTW: in jekyll I had a problem with unicode causing problems with page generation here. Solved it by stripping all non unicode via [^\x00-\x7F]+ regex expression. Thanks ProGM from http://stackoverflow.com/questions/20889996/notepad-how-to-remove-all-non-ascii-characters-with-regex

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• Feb 13, 2015

  6x6 tap code experimentation

  Tap codes has a pretty cool history, you can read more about it in the wikipedia entry for tap codes. A minor issue is that the C and K in the 5x5 tap codes are mushed together. What if we extend the table to 6x6. And what if we arrange it in different ways. Here is just some experimentations to that reguards.

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