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  1. J

    Looking for Picaxe/L293D half step truth table

    Trying to half-step a bipolar stepper motor (which I'm driving just fine using full-stepping) I've searched and searched the net and the forum and can't find a truth table to apply to four outputs of a Picaxe feeding the four inputs of a L293D which in turn feeds the motor. I've found one or two...
  2. J

    Problem reading from MCP23016

    Sorry to take so long to get back on this after you guys responded to my query so promptly... after trying every other possibility I did a thorough check of the PCB and discovered two slightly dodgy solder joints!!! I'm still so lacking in confidence about Picaxe stuff that I automatically...
  3. J

    Problem reading from MCP23016

    Well now... in frustration and bearing in mind what you guys have suggested and what I have learned since started building the code for this project I have re-started from scratch and put together a simple bit of code to set the i/o directions and read the inputs and flash an LED on that one...
  4. J

    Problem reading from MCP23016

    Have tried i2cslow but there is no change. I'm not familiar (newbie to i/o expanders!) with how to set the register format for ports A and B as blocks or sequential and how this works or even the reason for doing it... I can see it referenced in westaust55's control map but can't find the note...
  5. J

    Problem reading from MCP23016

    oops, the w3 was a typo from where I was experimenting with outputting just the b2 and b3... it should of course be w1! BTW the b2 data, from GP0 which are all configured as inputs, worked perfectly. But the outputting the b3 data, from the GP1 port (mix of inputs and one output) was definitely...
  6. J

    Problem reading from MCP23016

    Hi all, I'm trying to read from the ports of an MCP23016. GP0 port inputs are all configured as inputs. GP1 has been configured as 7 input pins (GP1.0 - GP1.6) and one output pin (GP1.7). I'm trying to read four or more inputs on GP1 to supplement the eight GP0 inputs to give me 12 inputs, with...
  7. J

    Code for mini bipolar steppers?

    oops...just noticed that Alan IS AlleyCat! Duh. Have had an incredibly busy few days/nights but will start to pick my way through your suggestions asap. J.
  8. J

    Code for mini bipolar steppers?

    Thanks too AllyCat. I'm not sure what load the motor will be driving yet, but had anticipated making it as little as possible by using the screw shaft to create a linear movement or having the item being moved fairly well balanced and needing only to be nudged in either direction by the motor...
  9. J

    Code for mini bipolar steppers?

    Hi Alan, that looks very interesting, thanks for taking the time to make your observations and suggestions!!! I think I understand what each of your suggestions is based on/doing and will sit down tonight NZ time and have a go with them! Watch this space! Jay
  10. J

    Code for mini bipolar steppers?

    I'm helping friends create some small animated figures and have sourced some very small, very cheap bipolar stepper motors (see pic) which will be ideal to create movement of arms, etc. However I am having difficulties successfully driving them. I'm trialing them using an existing combination...
  11. J

    Problem addressing two (or more?) I/O expanders via i2c

    Thanks everyone, I found the problem... knowing how little knowledge I have of this stuff I too readily jumped to the conclusion that I was getting something wrong due to misunderstanding the coding aspects and had not triple-checked the breadboard jumper leads! Ruling out the decimal/hex aspect...
  12. J

    Problem addressing two (or more?) I/O expanders via i2c

    Hi guys and thanks for your prompt thoughts! The second MCP23016 (they're on a breadboard) is definitely set for address 001. And when I take the first MCP23016 out of the circuit and change the second's address pins to 000 it responds exactly as the first one was doing. Lol... I was...
  13. J

    Problem addressing two (or more?) I/O expanders via i2c

    Using this code: hi2csetup i2cmaster, 64, i2cfast, i2cbyte I can set up and communicate with a MCP23016 I/O expander at address 01000000 and do anything I want with it. Substituting 0x40 for the 64 works just as well. I'm working on the implication that decimal 64 and hex 0x40 both equal binary...
  14. J

    External eeprom read/write problem

    Thanks guys, my problem seems to have been more or less along the lines of where you both were asking questions and making suggestions. I have tidied up the mix of bytes and words etc. and everything is running now as I had hoped. The lesson learned is to be much more careful and knowledgeable...
  15. J

    External eeprom read/write problem

    I think you guys' suggestions and questions have pointed me towards where I got all mixed up regarding eeprom addresses, bytes, words, etc. I'm currently re-doing how I assemble data for writing into the eeprom addresses and being more thoughtful regarding how I assign addresses to 'tracks', and...
  16. J

    External eeprom read/write problem

    Hi guys, thanks for your prompt replies! I'm very new to eeprom stuff and have just scaled up some basic trials I did which seemed to work ok... but maybe those early successes were only the result of ignorance disguised by dumb luck! HIPPY: In my early fumbling attempts with eeproms I seemed...
  17. J

    External eeprom read/write problem

    I'm blundering my way through writing data to a 24LC256 eeprom then retrieving the data but finding I have corruption issues. The data is currently sampled by a 20M2 from two sources and written in real time into the eeprom as two 'tracks' of data. Track 1 data (used to control a servo motor)...
  18. J

    AXE027 drivers installed etc. but "can't find hardware"

    A couple of days ago my trusty laptop died while I was using the Picaxe Editor. Looks like it was a power system thing... the laptop just went dead. I've transferred all my files to an external drive and for now am using that on an older PC running Windows 7. I've downloaded what seems to be...
  19. J

    Serial data problem

    I'm intending to eventually use a 14M2 chip to poll several switches (and possibly a potentiometer) and output a qualifier and value to show when each switch is pressed or not, sending the data down a serial line to several 'receiver' 14M2 chips. For the moment I'm getting my head around it by...
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