A shiny new collection of boards arrived today, so they’ve been unpacked and stuffed into storage awaiting being built up!
This is the first run of boards for the Breadboard PSU project, which now awaits some missing components and then a stencil to be cut by Ponoko. Hopefully in a week or two we might actually have completed some boards and have them available to buy!
For anyone actually following the SVN tree for the NTP Server, should be aware I’ve embarked on source changes to see how well the XMEGA chip works. This means there’s a tag for the last version which “worked” on PCB 1.3 (tagged as board-1.3) and a new branch called xmega-test which is where I will be .. well breaking everything!
The xmega-test tree may eventually be merged into trunk, probably about the time version 1.4 actually gets made. For now, don’t pay too much attention to it.
Above is the shiny new XMEGA development board which arrived a few days ago. I have had a plan for a while to switch the NTP Server project from the smaller MEGA microcontrollers to something a bit larger.
It’s been something of an ordeal to get just basic features of the board functioning. I appear to have tripped over some sort of bug in the Linux USB CDC code since it utterly refuses to treat the USB Serial bridge on the board as anything useful at all. Thankfully I wasn’t planning on relying on any bootloader in the main XMEGA chip, so lacking the bridge is an annoyance rather than a complete killer – the board still breaks out two further TTL-level USARTs (as well as SPI and I2C!) so I can actually work around it fairly easily.
Otherwise the board is quite neat. It has the requisite blinky LEDs (8 of them!), a bunch of buttons arranged the way I tend to do so (they pull the input to ground, and rely on an internal pull-up in the uC), RTC crystal, along with stuff slightly less useful to me now (a speaker wired up to the DAC, a temp sensor, a light sensor, and 1MB of SDRAM). What’s great is none of this takes away from having a decent number of IO pins left over. They’ve also made sure that while the firmware on the bridge chip needs some improvements, the hardware has been built to support a number of interesting future uses for the bridge chip.
So far I’ve managed to also validate I can reflash the USB bridge chip with arbitrary code, since it has a DFU bootloader on it. I think the only things they’ve got wrong is they could have staggered the USB bridge chip off the accessible JTAG port as well as the main XMEGA chip, but instead it’s JTAG interface is test points on the underside. And it has unpopulated footprints for flash, which considering it’s maybe a couple of bucks for 1MB of flash is a bit cheap to leave off.
We’ll see how this goes. It’s looking at least promising enough I’m willing to consider switching to the XMEGA line for the next major board revision of the endless NTP Server project!
As usually happens right after I get a new hardware build underway, and completed, I seem to find myself with the schematics and PCB layout open and with new ideas. This tends to happen after each build because I find myself only thinking about how it’s laid out when I get out the tweezers and solder.
This tends to be the way I find I develop these boards. It’s very focussed on one side of the design (usually split very sharply along hardware/software lines) and then will shift sharply into the other side. The last few weeks have been entirely about software (redesigning the way ethernet TX works, arbitrary UDP send, and a DHCP client). Now it’s all about the hardware, which parts I’m using and why.
So another round, and another set of ideas. It’s now clear there will be a new design of the Hardware NTP Server board, and it may be a significant set of changes as it looks like the open source toolchain has matured enough to make using the XMEGA line of microcontrollers an option.
I think each time I do a new hardware design I swear this time is the final version.
I think this must be the third reboot.
In any case, welcome yet again to yet another reboot of a mostly-tech blog. This time there’s going to be a bit of a difference, since this will also be home to documentation on my various (and occasionally working) electronics projects.
There will also probably be some commentary from time to time, and status updates on how much magic smoke I released this week.
In the mean time, have a poke around while I sort out my docs and resources.