02-26-2015, 10:40 PM
(02-26-2015 07:32 PM)rprosperi Wrote: [ -> ]Someday Walter, you must document the full Naval taxonomy of HP Calculators. For example, what is the 34S? Destroyer? E-Boat?
Trojan horse? Submarine? Life boat?
(02-26-2015 07:32 PM)rprosperi Wrote: [ -> ]Someday Walter, you must document the full Naval taxonomy of HP Calculators. For example, what is the 34S? Destroyer? E-Boat?
(02-26-2015 09:43 PM)MarkHaysHarris777 Wrote: [ -> ]Whoa... definitely worth looking into... I was not aware of the 'Teensy' category either. That little fellow would fit anywhere; question is whether it has enough pins (although, the idea of using more than one for parallel processing and process management is more feasible with low power using two or three of these!). Thanks for the tip. Have you programmed the 'Teensy' ?
(02-26-2015 07:27 PM)jch Wrote: [ -> ]Marcus,I have one of these Teensy boards. I wrote a few test programs on it to confirm that the USB interface is fast and reliable, then I just put the thing into my toolbox for future projects. I don't remember that it was particularly low power, except in sleep mode, but it certainly is powerful. It uses an ARM Cortex-M4 MK20DX256 32 bit processor running at 72 MHz. At that clock speed it will use quite a bit of power unless it is sleeping. With all internal peripherals turned on it consumes about 31 mA operating, and you need to add any current consumed by driven outputs to that total. While it is sleeping with all internal peripherals turned off, it consumes .61 mA. So if you operate one of these with batteries, you would want to use AA cells not coin cells. With 2500 mAH AA cells you could get about 80 hours of program running time, or about 1/2 year of off (Sleep) time.
Maybe a Teensy 3.1 could do the job ? It's tiny, quite cheap, low power and have horse power.
https://www.pjrc.com/teensy/teensy31.html
Regards.
Jean-Christophe.
(03-01-2015 01:37 AM)BarryMead Wrote: [ -> ](02-26-2015 07:27 PM)jch Wrote: [ -> ]Marcus,I have one of these Teensy boards. I wrote a few test programs on it to confirm that the USB interface is fast and reliable, then I just put the thing into my toolbox for future projects. I don't remember that it was particularly low power, except in sleep mode, but it certainly is powerful. It uses an ARM Cortex-M4 MK20DX256 32 bit processor running at 72 MHz. At that clock speed it will use quite a bit of power unless it is sleeping. With all internal peripherals turned on it consumes about 31 mA operating, and you need to add any current consumed by driven outputs to that total. While it is sleeping with all internal peripherals turned off, it consumes .61 mA. So if you operate one of these with batteries, you would want to use AA cells not coin cells. With 2500 mAH AA cells you could get about 80 hours of program running time, or about 1/2 year of off (Sleep) time.
Maybe a Teensy 3.1 could do the job ? It's tiny, quite cheap, low power and have horse power.
https://www.pjrc.com/teensy/teensy31.html
Regards.
Jean-Christophe.
(03-02-2015 06:10 AM)MarkHaysHarris777 Wrote: [ -> ]I'm definitely going to play with one of these soon. I am suspicious that this 'teensy' board will have speed stepping or at least a way to reduce the main clock (the WP34s 'SLOW' mode) which will reduce the current drain; most of the time we really don't need the ARM to be running so dang fast that it sucks our batts dry...
(03-02-2015 09:09 PM)jch Wrote: [ -> ]Barry, I must agree. Compared to the intake of HP-25C processor (1µA sleeping...), Teensy seems (very) greedy.The processor is a POWERHOUSE it is designed for HIGH POWER 100 mA sink or source outputs. It was never intended to be a low power device. Since it gets up to half an amp of continuous power from the USB port, saving current was never a design consideration for the teensy.