2 ms·
I suppose having the small DRAM footprint is required to meet extremely low power requirements. How low power is it? The CPU has a 18.6 μA/MHz Run mode at 3.3
by kristianp 1y ago
I suppose having the small DRAM footprint is required to meet extremely low power requirements. How low power is it? The CPU has a 18.6 μA/MHz Run mode at 3.3 V [1], so 61μW! I wanted to know more about the power harvesting applications though.
[1] https://www.st.com/resource/en/datasheet/stm32u5f7vj.pdf https://www.st.com/resource/en/datasheet/stm32u5f7vj.pdf
- deleted 1y ago[deleted]
- peerst 1y agoThe development was funded by a research project where the coordinator was a manufacturer of thermal energy harvesting devices. That's why we focussed on power most. That requires certain choices for CPU, RAM. We also have a lot of energy management hardware on the board: All PMODs can completely switched off. There is a separate wakeup logic that triggers when the capacitor that gets charged by the harvester has reached a certain charge level and many more. The challenge with using Erlang for systems like that is that it has a boot phase which it needs to get through until we can manage energy from the Erlang level. So we either need to have enough charge to get through the whole boot or we need to manage the boot process to and do it in chunks then sleep again. That's what we want to find out with this hardware but first we needed to squeeze in Erlang VM, RTEMS, TCP Stack and all of the Erlang objects to be useful (first goal was reach the shell). That's where we are right now.
- kristianp 1y agoThanks for your detailed reply. What are the uses for that kind of thing? Does bluetooth low power fit into that kind of power budget?