Forth code for Mecrisp (+Stellaris) on STM32 and MSP430
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flabbergast 97c0fb8e4a Reorg: replace_constants, resolve_includes. 3 years ago
..
ex Wiegand: WIP/testing. 3 years ago
README.md Update READMEs. 3 years ago
always.fs Initial. 3 years ago
board.fs Reorg: replace_constants, resolve_includes. 3 years ago
core.fs Reorg: replace_constants, resolve_includes. 3 years ago
dev.fs Initial. 3 years ago
freeze.fs Initial. 3 years ago
jz4-blip.hex Initial. 3 years ago
jz4-release.hex Initial. 3 years ago
rf-gw.fs Sbo: add deploy-sht31d sensor sources. 3 years ago
sleep-test.fs Playing with sleep-test and msp430 bare board. 3 years ago
wieg-gen.fs Wiegand: WIP/testing. 3 years ago
wieg.fs Update READMEs. 3 years ago

README.md

This code runs on the JeeNode Zero revision 4.

Low power

On regular power-up, the boards takes about 6mA. The LED takes about 1.5mA, lowering from 16MHz to 2.1MHz saves also about 1.5mA. (All on 5V through the regulator.)

Trying low power sleep (waking up on LPTIMER), with the "factory" firmware, tested with flib/stm32l0/sleep-extra.fs code, I got cca 11-12uA consumption in sleep, with 5V source through the regulator. However powering the regulator with 3.3V and sleep gives about 22uA consumption. Powering with 3.3V directly to the "battery" pin asks for the 12-15uA of power (seems to be a tad higher with TX/RX pins connected).

There is a blog post in which jcw measures power consumption. Roughly the same numbers as here, except the very low power stuff is reported lower: 6.5uA with the setup as above and 3uA with GPIOs in Hi-Z. Well. (Switching GPIO to Hi-Z mode does save about 3uA.) He reports that the regulator takes 0.5uA, and the radio in sleep 0.1uA.

Hm. I think most of the extra consumption I see on my jz4 is actually consumed by the regulator: Directly powering an L041 (on my sbo board) with no regulator in sight gives about 2uA consumption in sleep on 3.3V; powering my bat board with L052 through a different regulator (NCV8170) with 5V yields about 4uA in sleep.

I mean 11-12uA through the regulator is not too bad, but this needs either LiPo or 3 AA or something like that. For a direct supply to vdd (like a CR2032 coin cell or 2 AA), the best course of action would be to cut a trace somewher between the regulator and vdd. This is hard to undo. Or just accept 15uA consumption, this is still fine for a year on a CR2032.

Credits

Most of the code here comes, one way or another, from jcw's embello repo.