Search found 9 matches

by mikronauts
Sun Sep 29, 2019 12:14 am
Forum: General Discussion
Topic: How to work with 3 SPI slaves in Arduino ESP32 add-on
Replies: 2
Views: 201

Re: How to work with 3 SPI slaves in Arduino ESP32 add-on

see https://www.mikronauts.com/raspberry-pi/raspberry-pi-analog-to-digital-conversion-experiments-and-howto/ I used a 74HC138N to generate eight chip selects from three digital output. use CS0 as /EN, use three gpio's for the channel select inputs. I am trying to control 3 SPI slaves from one SPI co...
by mikronauts
Tue Aug 20, 2019 2:35 pm
Forum: Documentation
Topic: ESP32 ISA reference manual
Replies: 12
Views: 1891

Re: ESP32 ISA reference manual

Very unfortunate. I was thinking of writing an assembly language virtual machine for my compiler... on other 32 bit risc processors an optimized assembly vm ran 4x+ faster than a C version, in anout 1/10 the space. I don't think we have any update to what is shown here: https://www.esp32.com/viewtop...
by mikronauts
Sun Jul 28, 2019 12:41 pm
Forum: Hardware
Topic: 100K spi transactions per second
Replies: 3
Views: 394

Re: 100K spi transactions per second

15us intervals do seem excessive. Perhaps there is a configurable parameter in the spi master library or the rtos for minimum cs enable/disable periods? If not, maybe you could use the ulp to handle the spi transactions? Or use interrupts for spi receive and handle them on the other core? Worst case...
by mikronauts
Sun Jul 28, 2019 1:46 am
Forum: ESP32 Arduino
Topic: ESP32-Cam and SD Card
Replies: 10
Views: 2405

Re: ESP32-Cam and SD Card

Any luck with gpio16?

I just got my modules a few days ago.
by mikronauts
Sat Jul 27, 2019 3:16 pm
Forum: Hardware
Topic: 100K spi transactions per second
Replies: 3
Views: 394

Re: 100K spi transactions per second

That code sets the spi clock to 1.5Mhz, whereas the mcp3002 spec allows for 3.2mhz at 5vdc. Run the adc at 5v, use a voltage divider on miso, and increase the spi clock. Hi. I want to sample from an MCP3002 SPI ADC 100K times per second. I'm currently using the following code and only archiving abou...
by mikronauts
Thu Jul 25, 2019 2:56 pm
Forum: Hardware
Topic: very very slow pwm singal generation
Replies: 4
Views: 502

Re: very very slow pwm singal generation

Just use a timer interrupt Hi WiFive, This was the other option I was thinking of doing. I was hoping that maybe the ledc module could do this. I'd say if the timer has a period of 20 mins with a 10% duty, then a variation of 5% or less would be preferred. I'm not too familiar with the esp32's timer...
by mikronauts
Tue Jul 09, 2019 12:29 am
Forum: Showcase
Topic: HC-SR04 using RMT - very fast
Replies: 15
Views: 4494

Re: HC-SR04 using RMT - very fast

I was pointing out that worrying about the impact of integer vs floating point math (single or double precision) is not worth the effort, as even the slowest method is totally insignificant compared to the meadurement interval. The time taken to perform that calculation is less than 1/1000 the time ...
by mikronauts
Sun Jun 30, 2019 2:33 pm
Forum: Showcase
Topic: HC-SR04 using RMT - very fast
Replies: 15
Views: 4494

Re: HC-SR04 using RMT - very fast

The time taken to perform that calculation is less than 1/1000 the time to get the distance from the hcsr04.

Insignificant.
by mikronauts
Mon Mar 25, 2019 6:49 pm
Forum: Showcase
Topic: HC-SR04 using RMT - very fast
Replies: 15
Views: 4494

Re: HC-SR04 using RMT - very fast

I would be VERY surprised if the compiler did not perform constant folding by default. Hello, First of all thank you for your code it works perfectly. now i'm traing to simplify the ligne: distance = 340.29 * ITEM_DURATION(item->duration0) / (1000 * 1000 * 2); Because the μC works for nothing if we ...

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