Alternative WP34S flashing using Arduino

[adamkov]

Flashing WP34S using Arduino Nano V3.0 as a programmer
Written by Adam Kovesdi
18th of February 2014

Introduction

In this document I will show you how to use your $10 Arduino Nano clone to flash a HP30B to a WP 34S scientific calculator. There is no need for a special cable or physical serial port. Just the Arduino a cheap breadboard two small alligator clips and a few wires. You will also need a computer with a free USB port running Windows.

Requirements

• Windows PC with a free USB port
• Arduino Nano V3.0 or compatible clone with USB cable
• Breadboard
• Wires for the breadboard
• Alligator clips soldered to wires. This is for powering the calculator and providing a common GND for serial communication
• Paper clip (to operate RESET button on the back of the calculator)
• WP34S firmware
• WP34S manual
• MySAMBA program
  

Sources

Arduino http://dx.com/p/nano-v3-0-avr-atmega328-...ino-118037
WP34S firmware http://sourceforge.net/projects/wp34s under Files
WP34S manual http://sourceforge.net/projects/wp34s under Files/doc
MySAMBA program for flashing http://sourceforge.net/projects/wp34s under Files/FlashTool

Connecting to the calculator

The following diagram shows how to wire the arduino to the calculator
   

Legend

• Red wire with alligator clips on one end connects from Arduino pin 3V3 (PIN17) to calculator Battery terminal +
• Black wire with alligator clips on one end connects from Arduino pin GND (PIN29) to calculator Battery terminal -
• Blue wire connects from Arduino pin D1/TX (PIN1) to calculator J33 - see drawing above
• Green wire connects from Arduino pin D0/RX (PIN2) to calculator J35 - see drawing above
• Purple wire connects from Arduino pin RESET (PIN3) to Arduino pin GND (PIN4) - if you forget this the Arduino’s Atmel microcontroller will intercept serial communication and flashing won’t work
  

See the following picture I took during flashing. Note you have to hold the RX and TX wire in place when clicking send in MySamba software (see later).
   

Step-by-step flashing instructions

1. Run MySAMBA program and select the proper COM port for the Arduino serial adapter. Usually COM3 on my machines.
2. Select calc_full.bin (or your desired flash image) in MySAMBA, Do not click Send File button yet!
3. Turn the calculator on by pressing and releasing ON/CE. Make sure it is on.
4. Short ERASE pins on the back of the calculator with a piece of wire and keep it shorted until step 7 (see picture)
      
5. Press and release the RESET button on the back of the calculator with a paperclip
6. Press and release ON/CE on the calculator to turn it on again.
7. Remove short to ERASE pins
8. Press and release the RESET button on the back of the calculator with a paperclip
9. Press and release ON/CE on the calculator. It will not appear to turn on.
10. Push RX, and TX wires in place and keep them there (see picture)
       
11. Click “Send File” in MySamBa and wait for it to finish (approximately 20 seconds). Arduino TX LED will blink. If this step fails, return to step 3 and follow the instructions again - for me it never worked for the first time. Be persistent and keep on trying. Make sure RX and TX wires are making contact.
12. You can release RX and TX wires
13. Press and release the RESET button on the back of the calculator with a paperclip
14. Press and release ON/CE on the calculator.
    

You should now have a WP34S

Useful documents, resources

• WP34S manual page 149 on flashing
• http://commerce.hpcalc.org/34showto.php
• http://www.hpmuseum.org/cgi-sys/cgiwrap/...ead=230333
• http://www.thereminworld.com/Forums/T/29...b-to-wp34s