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Juan J. Martínez
Works at Memset Hosting Ltd
Lives in Godalming, UK
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Juan J. Martínez

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The Software Freedom Conservancy provides a non-profit home and services to Free, Libre and Open Source Software (FLOSS) projects.
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Juan J. Martínez

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Running a simple test. The tiles don't match perfectly and after some research I'm inclined to think I can't fix it. I suspect there's some delay when changing from one byte to the next one, but because that part is happening in the external SRAM, there's little I can do :(

My idea to render video from external SRAM isn't perfect. To be honest, I'm still surprised it works at all, so no complaints! ;)
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Juan J. Martínez

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The FCC approved the policy known as net neutrality by a 3-2 vote, with FCC Chairman Tom Wheeler saying the agency will ensure that no entity "should control free open access to the Internet."
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WTF? I have a #YouTube only profile with a #G + page I don't want (or use for that matter); you can't change that but if you want to use a free service... fair enough Google.

Now Google created a YouTube Channel for THIS G+ account that will be shown in my G+ profile no matter what.

They show you this (see the screenshot) in your G+ profile, but when you check the YouTube settings they tell you that the only way to remove the channel is actually removing your G+ profile. Not nice!

OK, I may do it :) I don't have a Facebook account, but... do I need a G+ account? What will happen to my #Android phone? Not nice...
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Juan J. Martínez

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Exciting progress!

The bottom waveform is my "hello world" in 6502 assembler pulse-width encoded into a wav audio file. The top waveform is the output of the Arduino after capturing the playback of the "hello world" (I play the wav in my laptop, the audio gets into the MCU that performs an analog to digital conversion and plays back the audio that gets recorded in by Audacity; there you are: a cheap oscilloscope!).

The result looks close enough. The important thing are the points where the signal crosses zero, particularly the distance between the points.

Yes, looks like I'm close to be able to read my programs from... a media player (not cassette, of course).
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Scrolling!

I was right, the pull-down resistor wasn't quite right. I've found a more suitable value and now the interference is gone!
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"Paela"!
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Pedro-Juan Ferrer Matoses's profile photoJuan J. Martínez's profile photo
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Oh, noooooo. Esta es valenciana hecha por una valenciana, y certifico que estaba buena :)
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Juan J. Martínez

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Yay! Managed to re-target CC65 to use my project's VM!

I did't add support for the libc, just my syscalls (that look kind of like old-DOS conio.h).

As you can see it uses more bytes to do the same thing (the equivalent assembler program is ~40 bytes).

But look at the difference: https://gist.github.com/reidrac/eb5ac9d453efe1fc7a63

That link shows C code (clean an easy), generated ASM code (without the runtime) and "hand coded" ASM.

If I'm going to write some programs for my microcomputer, now I can use C ;)
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Apple simply does not play well with other vendors when it comes to standardization. The same sort of things we once criticized Microsoft for doing long ago, we give Apple a pass on today. They’re very content to play in their own little sandbox all too often.
— February 24, 2015 — Apple's Web? The Pointer Events specification just became a W3C Recommendation. For those unfamiliar, it’s an …
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Yay!

After two weeks of hard work I can finally load programs into my project using audio (quite basic pulse width encoding).

I had a lot of problems understanding the MCU internals. I tried with ADC at first, but my decoding code was too slow... until a realised that I don't need to convert from analog to digital at all! The only thing I need is to be able to measure the time between high/low changes (eg, ones are longer half-pulses than zeros), and a "pin change" interrupt is more than enough.

In the video I'm showing all current parts of the project but the keyboard (I need to re-solder the cables): the audio is decoded and the result is loaded into SRAM to be executed in the 6502 virtual machine.

The audio in disrupts the video output and I'm not sure if I'll be able to fix that, but so far I'm quite happy with the results :)

I added an exta speaker for the video, because it's nicer if you can listen to the audio, but is not needed.
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I think the circuit is almost finished, and that's a good thing because... I'm running out of space! ;)

I may add some passive components, but the basic structure is there.
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Just amazing! A Castlevania game for the ZX Spectrum!
Download this nostalgic 8-bit action platformer for your shiny new ZX Spectrum. Find out why Belmont clan mysteriously disappeared for many years!
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Tagline
Software developer, open source coder/advocate and amateur gamedev
Introduction
I'm an experienced IT professional with a strong open source background, both in system administration and programming. Currently I'm focused on Python, Django, systems integration and task automation.

Currently based in Godalming (UK), I'm developer manager (read: lead developer) at Memset Hosting Ltd.

The opinions expressed here are my personal thoughts and do not necessarily reflect those of my employer.

One Game a Month 2014:
http://www.usebox.net/jjm/one-game-a-month/
Bragging rights
Made one game a month for a year
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Godalming, UK
Previously
Guildford, UK - Elche, Spain - Bilbao, Spain - Valencia, Spain - Exeter, UK - Reading, UK
Links
Work
Occupation
Lead Developer
Employment
  • Memset Hosting Ltd
    Lead Developer, present
  • Open Sistemas
    Infrastructure Manager/Project Manager
  • Panda Software International
    Quality Assurance Technician
  • Freelance
    Dev/SysAdm/Whatnot
  • Its Media
    Software Developer
Basic Information
Gender
Male
Other names
Juanjo, jjm, jjmartinez, reidrac