Search found 10 matches

by Espagnole
Sun Mar 12, 2017 2:07 pm
Forum: General Discussion
Topic: Future WROOM modules
Replies: 6
Views: 1726

Future WROOM modules

What about next versions of esp32 (chip itself) and new versions of ESP-modules?
In December there were rumors about the next version: with the antenna connector, larger number of pins, larger memory.
by Espagnole
Fri Jan 13, 2017 8:20 pm
Forum: General Discussion
Topic: SDIO Interface
Replies: 27
Views: 6432

Re: SDIO Interface

Indeed, adding pullup resistors solved the problem. However my question is why pullups resistors are needed at all: each SD card has internal pullup approx. 47k and we have internal pullup that are possible to turn on. Whats more, pull up mustn't be inserted on DATA2 (GPIO12) because spi flash volta...
by Espagnole
Thu Jan 12, 2017 2:52 pm
Forum: General Discussion
Topic: SDIO Interface
Replies: 27
Views: 6432

Re: SDIO Interface

Mine doesnt start: sdmmc_cmd: sdmmc_card_init: send_scr returned 0x109 sd_card: Failed to initialize the card (265). Make sure SD card lines have pull-up resistors in place. I have no idea what do more. Connections are OK, resistors are also connected (even if not needed) IO13 - SD_DATA3, IO2 - SD...
by Espagnole
Sat Jan 07, 2017 5:16 pm
Forum: General Discussion
Topic: StackDepth for xTaskCreate, why so big values?
Replies: 4
Views: 1550

StackDepth for xTaskCreate, why so big values?

xTaskCreate has 3rd argument const uint16_t usStackDepth . It is the number of words to allocate for use as the task's stack. configMINIMAL_STACK_SIZE is 1024, and it is lots of memory. Nevertheless it is minimum: it isn't enough to start a task and allocate anything inside. Why? What this memory is...
by Espagnole
Sat Jan 07, 2017 2:39 pm
Forum: General Discussion
Topic: freeRTOS: How to pass data between tasks
Replies: 8
Views: 2782

Re: freeRTOS: How to pass data between tasks

I don't get it you not know, when who or how the var was changed. it can be that an ealier process have change the var, the next process change too, then you miss the prev val. I pass data to a display. User wouldnt see a difference between data refreshed every 5ms and 200ms. Moreover when I refresh...
by Espagnole
Sat Jan 07, 2017 1:40 pm
Forum: General Discussion
Topic: freeRTOS: How to pass data between tasks
Replies: 8
Views: 2782

Re: freeRTOS: How to pass data between tasks

@rudi You have const string in memory so you can change the pointer. I have new data, so I would have a variable and change its value.
Anyway, if changing 1 word pointer is ok, changing 1 word variable wold be also.
Where is the key that "it is described everywhere as a bad idea"?
by Espagnole
Sat Jan 07, 2017 10:41 am
Forum: General Discussion
Topic: freeRTOS: How to pass data between tasks
Replies: 8
Views: 2782

Re: freeRTOS: How to pass data between tasks

I absolutely know what queues are. Take a look: I would like to show values from all sensors at some time on a display. After pressing a button, changing a view and presenting some text. After pressing another, going back to values. If I used Queues (xQueueCreate, xQueueReceive, xQueueSend), I would...
by Espagnole
Fri Jan 06, 2017 11:32 pm
Forum: General Discussion
Topic: freeRTOS: How to pass data between tasks
Replies: 8
Views: 2782

freeRTOS: How to pass data between tasks

Lets say I have 3 tasks: 1. for display and keyboard, 2. and 3. for ADC measurements. How should I pass data between them? int ADC_VALUE_1 = 0; int ADC_VALUE_2 = 0; void display_and_keyboard_task(void *pvParameters) { while (1) { if (shouldInit()) { init(); } if (xSemaphoreTake(display_semaphore, 10...
by Espagnole
Thu Jan 05, 2017 5:48 pm
Forum: General Discussion
Topic: Wait microsecond
Replies: 6
Views: 2260

Wait microsecond

How to wait eg. 40 microsecond inside a task? Time can be longer (interrupts execution), but shouldn't be shorter.

Is this optimal?

Code: Select all

vTaskDelay(configTICK_RATE_HZ / 20000); // 50us
by Espagnole
Mon Dec 26, 2016 12:27 pm
Forum: General Discussion
Topic: Should I use xQueueReceive for UART?
Replies: 1
Views: 664

Should I use xQueueReceive for UART?

What is more optimal way to use UART: using xQueueReceive or not and read one by one byte? I wont use any other event.type. while (1) { if (xQueueReceive(m_uart_queue, (void *)&event, 10 / portTICK_PERIOD_MS)) { if (event.type == UART_DATA) { uint32_t len = bufferEnd - ptr; if (len > event.size)...

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