Search found 11 matches

by guillep2k
Tue Feb 26, 2019 1:33 pm
Forum: Hardware
Topic: ESP Thermal considerations
Replies: 16
Views: 4697

Re: ESP Thermal considerations

Hi, It is a bit noisy with small ripples on 3.3V while transmitting. Why is the 10mOhm resistor needed? The goal was to pinpoint the source of the noise. Whether it's a noisy power supply or the drops are simply because of [acceptable] lack of regulation. I was looking for something dramatic that m...
by guillep2k
Sat Feb 23, 2019 12:40 am
Forum: General Discussion
Topic: Generate certs in production
Replies: 5
Views: 2158

Re: Generate certs in production

Regarding the third option, you could have a dedicated web server with https that takes a one time device request for signature of its own certificate; you could validate the server's certificate easily from the device side, while providing some fixed setup-use-only client-certificate to the server ...
by guillep2k
Fri Feb 22, 2019 11:58 pm
Forum: General Discussion
Topic: How to prevent http request from blocking task for too long?
Replies: 4
Views: 1874

Re: How to prevent http request from blocking task for too long?

Have you tried using a separate FreeRTOS task for the request? Check the xTaskCreate() function, and use semaphores to coordinate the tasks. YouTube is your friend!
by guillep2k
Fri Feb 22, 2019 11:52 pm
Forum: General Discussion
Topic: What would you like to see in The Next Chip?
Replies: 347
Views: 126765

Re: What would you like to see in The Next Chip?

I'd like to have support for UART in light-sleep mode, meaning: a not-so-small receive buffer (e.g. 64 bytes?) and the ability of waking up the cores after receiving some "complete" packet (either by size, character match, character timeout, etc.). A decent send buffer that works in light-sleep woul...
by guillep2k
Wed Feb 20, 2019 10:38 pm
Forum: Hardware
Topic: ESP Thermal considerations
Replies: 16
Views: 4697

Re: ESP Thermal considerations

I would like to add that it happened in a few other EV boards. And the current usually drops to around 100-150mA. In one of them manual reset helped. Hi, what about your power supply? Does it look stable? Can you look at it with an Oscilloscope? (With a 10 mohm series resistor between your power so...
by guillep2k
Tue Feb 19, 2019 4:58 am
Forum: Hardware
Topic: RAM & Flash cache efficiency
Replies: 5
Views: 1497

Re: RAM & Flash cache efficiency

Thank you. Does it make any difference if the lines are contiguous? I mean, if I access 2KB of contiguous memory vs. 2KB comprised of randomly located 32 byte chunks (as long as the chunks are properly aligned, of course)?
by guillep2k
Mon Feb 18, 2019 1:41 pm
Forum: Hardware
Topic: RAM & Flash cache efficiency
Replies: 5
Views: 1497

RAM & Flash cache efficiency

Hi. I've looked around a bit but I couldn't find an indication of how much actual RAM/Flash does 32K represent in the cache. I assume that the cache needs to reserve space for metadata information, like page source address, some kind of access tree, so I'd like to have a better idea about how many r...
by guillep2k
Mon Feb 18, 2019 1:15 pm
Forum: Hardware
Topic: Low power strategies without resorting to sleep modes
Replies: 3
Views: 2063

Re: Low power strategies without resorting to sleep modes

Thank you for your answer. CPUs will enter "wait for interrupt" idle state from the Idle task (i.e. when there are no other tasks to run). This saves a few mA (when CPU frequency is 240MHz). Does this mean that if I lower the CPU frequency for normal operation (e.g. 80, 40, 20 MHz) the "wait for int...
by guillep2k
Fri Feb 15, 2019 5:31 pm
Forum: Hardware
Topic: Low power strategies without resorting to sleep modes
Replies: 3
Views: 2063

Low power strategies without resorting to sleep modes

Hi. In my project I need to keep the ESP32 pretty much awake all the time because I'm processing input from several sources, especially UART (from GPS and GSM modules). That means I cannot use even the light-sleep mode or I risk corrupting the data coming from those devices. I come from other kinds ...
by guillep2k
Wed Feb 13, 2019 2:03 pm
Forum: Hardware
Topic: ESP32 GPIO slew rate/risetime
Replies: 3
Views: 2280

Re: ESP32 GPIO slew rate/risetime

Have you been able to measure those rise/fall times? I could use some figures. I've only got a 70 MHz oscilloscope.

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