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RFM12B reception

19/03/2012 – 15:28

Been debugging some RFM12B code again today. Reception is not as simple a matter as it could be because the documentation doesn’t really explain how it is supposed to work. I will try to make up for that in this post. Turn on receiver Wait for IRQ to indicate data available While RSSI bit in […]

By mojo | Also posted in avr | Comments (1)

RFM12B bit stream sync issue

22/12/2011 – 16:04

Been working with cheap RFM12B modules at work and discovered something interesting about them. A couple of things actually, the first of which is that the datasheet for the Si4420 IC it uses is much better. The main issue is that the serial data stream you get when receiving is not always aligned to the […]

By mojo | Also posted in avr | Comments (0)

XMEGA TWI (I2C) bus pull-ups

24/11/2011 – 16:32

The XMEGA 128A1 and XPLAINED hardware guide both suggest that TWI should work with the internal port pull-up resistors. Those pull ups are 50K+ and don’t pull enough for most devices. In short external pull-ups, say 10K, are essential.

By mojo | Also posted in avr | Comments (0)

Using the XMEGA DMA controller

04/11/2011 – 11:47

Finally got the XMEGA DMA controller on an ATxmega128A3 working. There is not much example code for it and the datasheet is not very clear, so I wrote this. The datasheet and examples don’t really explain the terminology well. A transaction is the complete cycle of the DMA controller. To start a transaction you load […]

By mojo | Also posted in avr | Comments (4)

Accuracy of clocks for timekeeping

31/12/2010 – 19:09

The MSF set clock I built earlier this year was using the AVR’s 16MHz crystal for timekeeping. It was fine during the warmer months but recently as temperatures fell it started to loose accuracy. By the late evening it could be as much as 30 seconds out, so I decided to add a new reference […]

By mojo | Comments (0)

Playstation Beatmania controller tested

01/08/2010 – 20:02

I got a Beatmania DJ turntable controller for the Playstation and it works perfectly with the Retro Adapter. It’s actually pretty simple; it emulates a digital pad. When the wheel is turned it just presses the up or down buttons on the d-pad. It doesn’t even use analogue for speed sensing etc.

By mojo | Also posted in microcontrollers, Retro Adapter | Comments (0)

The MSF signal is a bit of a mess

28/07/2010 – 00:06

I am working on another clock, this time with MSF (Rugby/The time from NPL)  radio time setting. I know, I need to document the last one… Anyway, I finished the decoder today. The MSF signal is frankly a mess. Things seem to have been added and then removed over the years. There are four different […]

By mojo | Also posted in avr, microcontrollers | Comments (0)

Mouse+Joystick “computer” mode for the Retro Adapter

18/06/2010 – 18:18

I have just finished updating mouse support on the Retro Adapter so that it now supports a mouse and joystick simultaneously. I am still trying to think of a good name for it but for the moment I am calling it “Computer Mode” because it is ideal for emulating machines like the Amiga or Atari […]

By mojo | Also posted in hardware, microcontrollers, Retro Adapter | Comments (0)

Maplin Soldering Fume Extractor mini review

12/06/2010 – 23:38

I decided it was time to stop breathing in leaded solder fumes and get a fume extractor. Being on a limited budget getting a new iron with one built in or a larger unit was out of the question. Actually we have an iron with extractor on it at work (Blackjack hot-air rework station with […]

By mojo | Comments (2)

Bliss Box violating my copyright, GPL and more

13/05/2010 – 17:26

I just spotted this: http://spawnlinux.dyndns.org/Bliss-Box/technical.html It violates my copyright on some of the images such as the schematic and connector diagrams. It also violates the GPL by using V-USB and not publishing the relevant code. Chances are it probably uses some of my GPL’ed code, and the author admitted that it is based off some […]

By mojo | Also posted in Internet, law | Comments (0)
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