Search found 719 matches

by ag123
Mon Sep 25, 2017 3:34 pm
Forum: Off topic
Topic: Counterfeit F103s
Replies: 24
Views: 498

Re: Counterfeit F103s

my guess is, it is probably more difficult and more expensive to make even clone , compatible or for that matter 'fake' chips compared to simply buying the real ones, unless of course if the fake chips totally doesn't work and are simply duds :lol:
by ag123
Mon Sep 25, 2017 3:20 pm
Forum: Projects
Topic: Anyone tried to make a 3D Printer controller?
Replies: 251
Views: 18785

Re: Anyone tried to make a 3D Printer controller?

i'm starting to think in terms if it may be worth it to have a 'highly optimised' marlin for stm32 instead, stm32 has lots of h/w timers, if we let the timers (generate the square wave train) run the motors, the isr may be able to do 'fire and forget' but the design may be drastically different. e.g...
by ag123
Sun Sep 24, 2017 5:30 pm
Forum: Projects
Topic: Anyone tried to make a 3D Printer controller?
Replies: 251
Views: 18785

Re: Anyone tried to make a 3D Printer controller?

unlike the more elaborate stepper motor controllers from ST, many of the A4988 RAMPS stepper motor controllers are rather basic https://www.pololu.com/file/download/a4988_DMOS_microstepping_driver_with_translator.pdf?file_id=0J450 and it would seem that it wouldn't be possible to share the step and ...
by ag123
Sun Sep 24, 2017 4:37 am
Forum: General discussion
Topic: Dhrystone and Whetstone Benchmarks for STM32F103
Replies: 173
Views: 11062

Re: Dhrystone and Whetstone Benchmarks for STM32F103

well, benchmarks are 'just for fun'. But yes, the f407 is a lot faster than f103 for floating point fpu accelerated code, u can ignore the milliseconds imprecisions, it is day and night differences :lol:
viewtopic.php?f=39&t=2001
by ag123
Sun Sep 24, 2017 4:16 am
Forum: Working / ported libraries
Topic: Free RTOS and idle loop()
Replies: 8
Views: 118

Re: Free RTOS and idle loop()

I think the integration between Arduino and FreeRTOS is merely to start the FreeRTOS scheduler, thereafter FreeRTOS takes over all the context switches from there. http://www.freertos.org/a00102.html int main( void ) { /* Setup the microcontroller hardware for the demo. */ prvSetupHardware(); /* Cre...
by ag123
Fri Sep 22, 2017 12:17 am
Forum: Ideas & suggestions
Topic: Differential ADC (ADC1-ADC2)
Replies: 14
Views: 316

Re: Differential ADC (ADC1-ADC2)

on this topic about noise, in part as i use low pass filtering, i've inherently 'escaped' some of the noise issues. ecg signals are in the low orders of 5 hz - 40 hz (accordingly the range do extend upwards to say 50hz or somewhat more but of low amplitude), nevertheless low pass filtering set at 40...
by ag123
Thu Sep 21, 2017 3:12 pm
Forum: Projects
Topic: Anyone tried to make a 3D Printer controller?
Replies: 251
Views: 18785

Re: Anyone tried to make a 3D Printer controller?

i'm halfway wondering if marlin or more correctly both marlin and 'gcode senders' if there are any desktop 'g-code sender' that routes g-codes to multiple 3d printer controllers i found at least this http://winder.github.io/ugs_website/ but i'm not too sure if the more popular variants e.g. http://o...
by ag123
Thu Sep 21, 2017 2:25 pm
Forum: Ideas & suggestions
Topic: Differential ADC (ADC1-ADC2)
Replies: 14
Views: 316

Re: Differential ADC (ADC1-ADC2)

thinking through this it would seem this differential adc could help remove some of that common mode noise, i could feed that ad8232 output into 2 ADCs and perhaps it may remove some of that artefact spikes :?
by ag123
Thu Sep 21, 2017 1:40 pm
Forum: Ideas & suggestions
Topic: Differential ADC (ADC1-ADC2)
Replies: 14
Views: 316

Re: Differential ADC (ADC1-ADC2)

oh well, i actually messed with this: https://www.sparkfun.com/products/12650 and of course there are cheaper 'knock offs' from here: https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=ad8232&_sop=15 (think the 'cheap' ones may not be as safe it's good to measure the resistances of the smd resi...
by ag123
Thu Sep 21, 2017 12:31 pm
Forum: General discussion
Topic: short on VBAT?
Replies: 5
Views: 167

Re: short on VBAT?

Btw, MMinis do not have 32kHz RTC crystal mounted, how did you wire it? thanks pito, this is tad ugly but it here is the hack, guess it's about time i solder a new MM :lol: https://i.imgur.com/aWySYZg.jpg looks ilke that huge blob of solder at the crystal joints looks pretty bad, would probably nee...