- Written by Akiba
I’m happy to announce the release of my latest design, the Freakduino-Chibi.Yes, there has been mixed reviews about the naming. It’s ranged from “seriously?” to outright laughter. I decided to go with it though because it does express two things that I think are important. The first is that it’s an Arduino-compatible board and the second is that it’s related to my original Chibi boards .
Before I get into the actual board, I should probably talk a bit about the background behind the design of the boards. The original Chibi protocol stack and Chibi boards were meant to be an entry level way for people to get involved in wireless sensor networking and data collection. But after observing people in Tokyo Hackerspace and in my microcontroller workshops, I realized that there were still some things missing.
- Written by Akiba
Sorry about the delay in releasing the ATXMega boards. There's some good news and bad news.
The bad news is that there won't be SPI DMA support. I was validating the SPI DMA feature and found that DMA transfers for an SPI master can't be made directly to an SPI port. They can only be made to a UART configured as an SPI master. This would have required swapping two pins, but still wouldn't have been much of a problem. The real issue is that when I configured a UART as an SPI master and sent data through it, I ran into what looks like a hardware bug that leaves some SPI transfers incomplete. Here's a shot of a 2-byte transfer:
Hence, I've made the decision that I won't be supporting the DMA to SPI feature. I apologize since I believe there were some people that were looking forward to that feature. For people looking for DMA'd wireless transactions, I'd recommend the EconoTAG from Redwire. Its based on the Freescale MC13224 and supports DMA to the radio FIFOs. It's also designed and supported by Mariano Alvira who is a frequent contributor to open source and the Contiki project.
The good news is that the memory to memory DMA feature is working so that people doing a lot of block copying can now offload that from the MCU.
Anyways, that was the last thing standing in my way to release the ATXMega boards. The boards are now in the shop and I've also put together a set that consists of an MCU board, radio, antenna, and standoffs.
Thanks for the patience and sorry about not supporting that feature. Here are the links to the products:
- Written by Akiba
Wow! Things have been unbelievably busy recently. Along with the part-time consulting, things have been heating up at the Tokyo Hackerspace recently.
I started a group with another member called "Wireless Wednesdays" that meets two Wednesdays a month. In it, we discuss and try out different things going on with wireless. The first meeting, we actually flashed an 802.11 router with DD-WRT and then demonstrated how to boost the transmission power, partition the networks between public and private, go into repeater mode, and do other fun things with the firmware. We also have a two group projects going on in a rural area outside of Tokyo. One of them is to instrument rice paddies with wireless sensors to help out the elderly farmers so they don't have to climb up the hillside terraces every day to check on the crops. The other project is to help take a census on wild monkeys and boars that keep feeding on the farmer's crops. If we can get a good estimation of the animal count, we can help them plant lower quality side crops outside of the main farm area so that the animals won't need to forage from the farmer's main crops. Not sure if that second one will be successful, but it sounds fun and we might be able to save some animal lives as well as help out the farmers.
I'm also hoping to set up a test bed managed by the group to test out some of the WSN work going on inside the IETF. There's been a lot of exciting things recently with the release of RPL (the 6LoWPAN Routing Protocol) by ROLL and an upcoming CoAP plugfest by CoRE (6LoWPAN application layer protocol).
I also taught my microcontroller class again at the hackerspace and updated a lot of my lessons. I've been meaning to post the lessons for a few months now, but have been so busy with new designs and other work that it kept on falling through the cracks. However I've been giving out the lesson notes to a few people and have gotten good reviews on them so I think they're ready to be published. Those should be going up soon, once I get a little bit of breathing space.
I've been working hard to get the ATXMega boards out the door. The first batch are fully assembled and tested and I actually finished writing the documentation last weekend. However I realized that just throwing the ATXMega's out into the wild may not be the best thing to do since they're quite different from the AVR ATMega chips. The number of new features are really amazing, and just as amazing is the amount of documentation you have to go through to figure out what you're doing. Because of that, I decided to postpone the release a bit and put together a software package that shows how to do some fundamental things on the new chips.
As an example of why the test code was needed, you can just take a look at the GPIO configuration. In the ATXMega, you can now configure each pin to be internally pulled down, pulled-up, wired-or, wired-and, or as a buskeeper. Each IO can also be configured as an interrupt and the interrupt can have three different priority levels. There's also slew rate control to increase the rise/fall times of the IO. There are now individual set, clear, and toggle registers for the direction and port registers which get rid of the need for read/modify/writes. And you can batch disparate GPIO pins from different ports together into a "virtual port" which can be accessed just like a normal GPIO port. Damn! The flexibility is great, but the options can make your head spin!
Anyways, so I put together a very simple test code package that hopefully can help make kicking the tires on the ATXMega a little bit easier. It's nothing comprehensive, mind you, but it should show how to get the basics going on the chip. You can find a tutorial I wrote on it here:
I also finished a Chibi port to the ATXMega and should be uploading that soon.
And finally, the boards will be released after I post the Chibi code and check over the documentation. Stay tuned...
- Written by Akiba
I just finished my first month of having the shop open and it feels pretty good. After I was able to open the shop up, I could finally get down to other pressing things like designing new boards and looking for interesting products to stock. There are also tons of other things that needed to be done like writing documentation and putting together tutorials on how to actually use what I’m selling. I think that’s one of the hardest parts about having a shop and one of the areas that can really make or break things.
I really enjoy scouting for new products. It gives me an excuse to buy a bunch of parts and try them out. There are a lot of duds, but the more things you try, the more ideas you get and recently, I seem to be bursting with ideas…well that or I’m going to have an aneurysm soon. I try to keep the theme of wireless sensor networks in mind when I’m scouting for products and you can see that a lot of the new products are somehow related to this, however there are a couple that get through because they’re just too cool to pass up. Here’s the rundown on what’s new: