Ok, got some numbers. Conditions: Main board: Teensy 3.6 Adata 8G class 4 sd card inserted. (different cards draw more or less) 128x64 mono OLED attached by I2C and lit up with a screen of text. https://www.velleman.eu/products/view/?id=439232 Serial1 connected to a level-shifter to a pc http://schmartboard.com/schmartboard-rs-232-module-710-0001-01/
http://www.analog.com/media/en/technical-documentation/data-sheets/ADM2023_1181A.pdf The level-shifter is powered from one of the 3.3v pins provided by the Teensy, ie, NOT from the Vin or VUSB that feeds the Teensy itself. (this is mostly just to protect the Teensy io pins from getting more than 3.3v from the level-shifter, but it also means the current draw number includes the level-shifter) RTS and CTS lines actually connected to level-shifter too. USB not connected. Power coming from a plain 5v supply to the Vin pin on the Teensy, with ammeter in series. on-board led lighted during sdcard access Voltage measured at the Teensy and while under load Running at 2mhz: While waiting for a keypress: 18.3ma @ 5.07v While writing to sdcard: 33-38ma @ 5.07v Running at 24mhz: While waiting for a keypress: 36ma While writing to sdcard: 59-66ma Running at 180mhz (default): While waiting for a keypress: 96ma @ 4.98v While writing to sdcard: 96-130ma @ 4.7v This is with no special tricks to go idle and draw low power. I think there are lowpower libraries that can do some things, and definitely there are purely eltronics ways to cut power and restore power based on serial activity. But my test code right now is just sitting in a loop reading the serial port. On Fri, Aug 24, 2018 at 6:36 PM Brian White <bw.al...@gmail.com> wrote: > Well that's a downside of working in an unorthodox location, I don't have > any way to measure current right now :) > https://photos.app.goo.gl/rq2TM5cWNV8NMkyi8 > > > On Fri, Aug 24, 2018 at 3:15 PM Fugu ME100 <b4me...@hotmail.com> wrote: > >> That sounds great. What sort of current draw are you getting? Quite >> curious. >> >> ------------------------------ >> *From:* M100 <m100-boun...@lists.bitchin100.com> on behalf of Brian >> White <bw.al...@gmail.com> >> *Sent:* Friday, August 24, 2018 20:12 >> *To:* m...@bitchin100.com >> *Subject:* Re: [M100] New Age Digital Storage Box (NADSBox) >> >> I was playing with the Teensy 3.6 some more last night and got it waiting >> & responding to commands by serial (the built-in ftdi usb-serial not via >> max232 yet), reading/writing to files in a fat32 fs on the sd, blinking the >> on-board led during drive activity, and displaying text on a tiny 128x64 >> 0.96 inch oled display via i2c. >> >> All while sitting at a counter at a diner. >> >> Because it didn't need anything but a laptop, usb cable, and the chip >> stuck on the end of the cable, and 4 jumper wires just for the oled display >> which was just for play anyway, probably wouldn't actually want that on the >> finished device. >> >> These arduino libraries and built in examples make it all pretty easy to >> get started. >> >> And teensy has an rtc built-in too. Needs another battery, but a cr2032 >> can apparantly keep the rtc going for about 17 years, so, not a problem. >> >> This 32 bit 180mhz cpu is overkill, but it's just handy having the sd >> card reader and usb port already built in. The cpu can be underclocked in >> software but I don't know if it goes all the way down to 4! >> > > > -- > bkw > -- bkw
