Search found 621 matches

by PeterR
Tue Nov 27, 2018 12:08 pm
Forum: ESP-IDF
Topic: How to use SPI from an interrupt?
Replies: 3
Views: 7495

Re: How to use SPI from an interrupt?

Difficult to comment without knowing what these shared resource are - however if you are talking about shared application data then: Your SPI task 1) fires up on ISR semaphore/event/queue, 2) reads application data, 3) launches SPI with copy of data, 4) waits for SPI completion, 5) Stores results so...
by PeterR
Tue Nov 27, 2018 10:47 am
Forum: ESP-IDF
Topic: How to use SPI from an interrupt?
Replies: 3
Views: 7495

Re: How to use SPI from an interrupt?

spi_device_transmit() queues a request, enables the SPI interrupt which should then run and start the SPI exchange. spi_device_transmit() calls FreeRTOS routine which should not be called from an ISR. Regardless spi_device_transmit() then waits for the transaction to complete as indicated by a item ...
by PeterR
Sun Nov 25, 2018 10:01 pm
Forum: General Discussion
Topic: POST to website
Replies: 1
Views: 2404

Re: POST to website

Get a faster uplink and/or server ;) One problem is that HTTP negotiates a connection on each POST/GET etc. So there is a lot of 'hello are you there', 'o yes I offer this', 'go on then here's my command' going on in each POST/GET. Each interaction has potentionally a large latency. MQTT and/or webs...
by PeterR
Mon Nov 19, 2018 11:50 am
Forum: General Discussion
Topic: BLE SPP example & UUID
Replies: 4
Views: 12577

Re: BLE SPP example & UUID

Thanks. I read the article again & it is all explained.
I should use a 128 bit UUID for my unique SPP and introduced with a 0x06 or 0x07 data type value.
All seems to make perfect sense.
by PeterR
Mon Nov 19, 2018 11:12 am
Forum: General Discussion
Topic: BLE SPP example & UUID
Replies: 4
Views: 12577

Re: BLE SPP example & UUID

Thanks. And this explains the binary advert: https://www.silabs.com/community/wireless/bluetooth/knowledge-base.entry.html/2017/02/10/bluetooth_advertisin-hGsf EDIT: So I am still confused as the advert contains the list of 16 bit adopted UUIDs. The SPP example shows 0xABF0. So if I should use a 128...
by PeterR
Sat Nov 17, 2018 1:15 am
Forum: General Discussion
Topic: MicroSD hangup
Replies: 19
Views: 19372

Re: MicroSD hangup

Printing frequency & especially the number of items you print at a time definitely makes a difference. I was running with stacks at least 1.25K to small for ages without issue. Started debugging & enabled some verbose & boom. Still finding my feet with ESP but back in the day 5K for a task with prin...
by PeterR
Fri Nov 16, 2018 3:03 pm
Forum: General Discussion
Topic: BLE SPP example & UUID
Replies: 4
Views: 12577

BLE SPP example & UUID

Just getting started with BLE. The ESP SPP example uses the 16 bit service UUID of 0xABF0 My understanding is that BLE does not have an SPP service and that we are not allowed to use 16bit UUIDs (unless we pay and register) for custom services. BT has the SPP as 0x1101 in anycase. Is the 0xABF0 exam...
by PeterR
Fri Nov 16, 2018 2:33 pm
Forum: General Discussion
Topic: MicroSD hangup
Replies: 19
Views: 19372

Re: MicroSD hangup

Perhaps we should jump over to https://www.esp32.com/viewtopic.php?f=2&t=7960&start=10 before I get charged with post hijacking :oops: I could not distill a small example. I think the mechanism described in my post is easy enough to review and follow though. Essential there was no multi-core protect...
by PeterR
Fri Nov 16, 2018 10:28 am
Forum: General Discussion
Topic: MicroSD hangup
Replies: 19
Views: 19372

Re: MicroSD hangup

@ESP_igrr My bad: v3.2-beta1-34-gfb7ba1baa The issue is described here: https://www.esp32.com/viewtopic.php?f=2&t=7960&start=10 and here https://github.com/espressif/esp-idf/issues/1651 My summary at the end of the first thread explains the mechanism (as I see it). Perhaps you could add comments to ...
by PeterR
Thu Nov 15, 2018 7:43 pm
Forum: General Discussion
Topic: MicroSD hangup
Replies: 19
Views: 19372

Re: MicroSD hangup

I had (what I believe to be) multicore & general reentrancy/race issues with IDF 3.1 SPI (& even 3.2-dev). Essentially my SPI transaction ended up hung on what I believe was a race condition. I have since moved to 3.2-rc1. This version adds a lot of C++11 atomics to the SPI driver and what seem to b...