I now pushed the thumbulator branch as the new master branch for CoreForth. The idea behind thumbulator is to have just enough of a host based virtual environment to compile Forth source, and dump the resulting binary which can then be flashed. The .elf file is therefore now just an intermediate file, it could be flashed, but contains only the core part. However, if thumbulator fails to run or produce a binary, it will silently still create a garbage binary, which won't flash properly. I guess I need to make that part more robust :)
When writing CoreForth, I got quite far with the assembly based pseudo code approach, but at some point, I wanted to switch to high level code. Metacompilation is probably the right approach but I felt it would require a rewrite of the whole system. Same with a tethered Forth. I also was using qemu for experimenting without hardware, and the 1.0 branch of CoreForth was just converting the Forth byte code into assembly sources for later compilation via an assembler.
qemu seemed a bit heavy though, and with thumbulator I found a lightweight way to have a host based environment to produce a target binary. This works as long as there are no fancy hardware dependencies at compile time, but usually, there aren't any ;) And if something is desperately needed, it is pretty easy to extend thumbulator.
Just checking ...
Call me a pessimist (or long term thinker), but the other day, I just had to check if my Pismo PowerBook G3 still boots, and if I can still compile the Newton Y2010 patch. The way things are going, it looks like I'll still be using my MessagePad when the next iteration of the Y2010 patch is due (around 2026).
Si4012 and CC1101
Something completely different for a change: I recently designed a simple sensor network, and wanted to keep the cost of the sensor nodes down while using the 434MHz band for range reasons. The Silicon Labs Si4012 transmitter fit the bill very nicely, but I was already happily using a Texas Instruments CC1101 radio as the receiver.
Below are the settings for the CC1101 and Si4012, the modulation is 2-FSK and the bit rate is 38.4kpbs. First the CC1101 register settings:
And this is the Si4012 configuration (these are properties, to be set via the SET_PROPERTY command:
When sending from the Si4012, the preamble (8 x 0xaa), the sync word (0xd391) and the CRC need to be added manually to the packet.
Slightly strange combination
Continuing the praise for the J-Link SWD/JTAG adapter, it works well in even slighly odd situations. The new Intel Quark D1000 is debugged via JTAG, but uses an IO voltage of 1.8V. My old Olimex ARM-USB-TINY-H adapter doesn't go as low, but using the J-Link with OpenOCD worked like a charm!
Things which Just Work
Both tools "just work" without any fuzz, and on my development platforms Mac OS X, Linux and Windows. The Saleae comes with very easy to use software, has nicely engineered hardware, extensibility and awesome support (three years warranty!). The J-Link is maybe not as sexy, but it handles the key task of debugging, flashing and interfacing with GDB without hiccups.
For both tools, cheap clones do exist, but it is a no brainer to spend a little more money to reward the excellent work that went into them.
PS: Yes, the Apple Newton also falls into this category, but I don't think that needs to be explicitly pointed out ;)
Little motes here and there
Since the internet of things is all the rage, I wanted to do some learning by doing, and set up an own small network to experiment a little. It seems that there are a lot of technologies to chose from, and that on all layers: Different radio technologies, different processors, different protocols and so on. I settled for now on SWAP as the protocol since it's easy enough, but I'm using the widely available NRF24L01+ chips for the radio layer. The CPUs are a mix of MSP430's, LPC1114's and STM32F0's, running either a bare metal program (MSP430 and STM32F0) or mbed (LPC1114).
It has been a very interesting experience so far, and in good hacker manner, doing things from first principle gives a lot of insights: How to get power consumption to the micro ampere level? How to build small and simple hardware designs? What are good antenna designs? What about quality of service, packet loss, etc? How to visualise data and use it in smart ways?
The biggest problem is however a very common one: What to actually build with all that stuff :)?
A Subjective Classification of MCUs
Newton Projects in Modern Times
I really like GitHub for easy hosting and version control of software project sources, but it is just not that easy to use for Newton NTK projects. Mark Mason's story of how he open sourced Dashboard is a great read about how he mastered the challenges of resource forks, lost sources, ancient version control systems and so on to get Dashboard onto GitHub. Even more, the stuff under the obsolete files folder is pretty hilarious ;)
tntk avoids these issues by being text based, but this comes at the loss of a graphical UI builder. I'm not too bothered by this, but it appears that the easiest way to go back in time and create Newton apps the way they were intended to be implemented is to get a fast and reliable PPC based Mac, install Classic, and head back to the future ;) - and don't forget to back up frequently!
Bluetooth related developments
Some updates from the Bluetooth side of things for the Newton: I have been able to compile Blunt 2 on Linux using mosrun, the excellent Mac OS enabled 68k emulator by Matthias Melcher. The only pieces missing are packing the compiled binary, and embedding it into a Newton package. This should finally allow to cover any scenario of Newton development without the need of Mac OS Classic.
I have also looked again into suitable Bluetooth modules, and it seems that the HC-05 module, some quite interesting options exist. The module can be purchased for 5-10$, it has an integrated antenna, and uses 3.3V as the power supply - it should be pretty easy to connect to the Newton's internal serial connector. By default, it is configured to act as a Bluetooth slave exposing a serial port profile, which is already quite useful: In this configuration, the Dock protocol can be run over Bluetooth without changes (only the internal serial port needs to be made visible to the Dock app). It won't allow establishing a connection from the Newton to any other device to use e.g. Neo and IC/VC, but for backup, syncing and package installation this would be good enough.
The HC-05 module should be reconfigurable though to use HCI as the Newton-side protocol, and this would make it a great candidate for Blunt. The only challenge is to implement a LPT to SPI converter and use the CSR tools to flip the configuration bit for HCI support.
Battery rebuild complete
Thanks to the awesome (both technically as well from an entertainment perspective) instructions by Frank Gruendel how to rebuild an Apple Newton batterypack, I managed to revive one of my old, flat packs. It took a while, and was at certain points quite frustrating, but definitely worth the effort. Frank is certainly right about the manufacturing tolerances, even with greatest care it seems that I managed to expand the pack in one or the other dimension to the point that the built in mechanism is not strong enough to push out the pack by itself. Thankfully, Frank has that problem also covered, and I can now enjoy 2500mAh of power :)