Woodstock power supply

[Paul Dale]

(01-08-2017 08:45 AM)PANAMATIK Wrote:  How much memory would be needed for this approach? Which ARM processor would you prefer for the LED 34S?

I'll need to discuss this possibility with my partners in crime. The keyboard layout and display wouldn't be easy to cut back but a catalogue based system ought to be possible to increase the number of functions well beyond the 34C (but not the 34S).

The current hardware has 2kb of non-volatile RAM, 4kb of volatile RAM (lost between keystrokes), 128kb of flash and (I think) 55 bytes of display RAM which we use as semi-volatile (it stays alive during powerdown between keystrokes but not a soft shutdown). I think the CPU is an Atmel AT91SAM7L128. All types of memory are stretched to their limits, so some headroom would be very much appreciated. We don't much of the available hardware in the CPU even though quite a bit is run to headers on the 20b/30b hardware. Marcus knows a lot more about this than I do, he is primarily responsible for the hardware support and features.

I don't believe we're tied to this CPU or even an ARM processor. There is essentially no assembly code in the firmware. We do need a C compiler (probably based on gcc) that supports long long ints both for integer mode and elsewhere, we don't need native floating point support.


Is there a form factor suitable 16 segment LED display? We rely on text messages a lot and this would simplify things I suspect -- without this we can do all letters except K, V and X on a 7 segment display if we've got direct access but some important symbols would still be missing (division, multiplication and addition are obvious ones). Going through the anode and cathode driver chips would limit things further but might be possible.

Is a GPS possible? Some SPI FRAM or equivalent for the library? IR printing would be nice of course.


Marcus is very busy with real life, so we'd likely require some assistance on the hardware side. The main firmware shouldn't be a big problem, it will be cutting features and reworking the UI code which I'm fairly familiar with. Which leaves the layout and UI to design.


Pauli