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by loboris
Tue Mar 21, 2017 8:26 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 4878

Re: only three slave can be attached in SPI ?

maybe i call spi_bus_add_device once, with a dummy CS pin number, and select CS via GPIO manually? why the API has this limit? You can set the divice configuration not to use CS ( spics_io_num = -1 ) in spi_device_interface_config_t structure int spics_io_num; ///< CS GPIO pin for this device, or -...
by loboris
Mon Mar 20, 2017 7:31 pm
Forum: Showcase
Topic: ESP32 with GSM modem - PPP over Serial (PPPoS) client example
Replies: 32
Views: 42928

ESP32 with GSM modem - PPP over Serial (PPPoS) client example

https://github.com/loboris/ESP32-PPPOS-EXAMPLE Tested with esp-idf v2.1 and latest esp-idf master branch If using with latest esp-idf (e6afe28bafe5db5ab79fae213f2e8e1ccd9f937c or later) a patch for components/lwip/api/pppapi.c is need. Use included pppapi.c.patch to patch the file or copy pppapi.c....
by loboris
Sun Mar 19, 2017 11:12 pm
Forum: Hardware
Topic: RTC with 32.768 kHz crystal
Replies: 10
Views: 8611

Re: RTC with 32.768 kHz crystal

ESP_igrr wrote:In the current ESP-IDF, using RTC as clock source isn't supported unfortunately. Expect to see support for this by the end of February.
Any news about RTC as clock source support ?
by loboris
Sun Mar 19, 2017 8:07 pm
Forum: Report Bugs
Topic: Getting real FlashID
Replies: 10
Views: 7811

Re: Getting real FlashID

... BTW, I was looking if I could do it my self using SPI_Common_Command(), but I didn't figured out how. Can you provide example how the SPI_Common_Command() function is working ? Maybe you could use the approach from https://github.com/whitecatboard/Lua-RTOS-ESP32 You have to patch 2 files in esp...
by loboris
Thu Mar 16, 2017 9:04 am
Forum: ESP32 IDF
Topic: Max tx length of spi_transaction_t?
Replies: 13
Views: 5422

Re: Max tx length of spi_transaction_t?

I have a buffer of 76.8K bytes(half of the LCD screen buffer), I want to use spi_master to transmit the whole buffer to SPI port in one transaction. After a trial, I found the maximum bytes that can be transfered in one transaction is 4095 bytes. It will send wrong data when the length is more then...
by loboris
Wed Mar 15, 2017 10:04 pm
Forum: General Discussion
Topic: Where is fourth SPI
Replies: 5
Views: 3155

Re: Where is fourth SPI

You can have multiple devices connected to each od HSPI and VSPI, just configure different pins for CS.
I've tested ILI9341 TFT Displays and it does not matter on which SPI bus it is connected or on which pins. It works without problems at clock speed up to 40 MHz.
by loboris
Wed Mar 15, 2017 7:40 pm
Forum: ESP32 IDF
Topic: Max tx length of spi_transaction_t?
Replies: 13
Views: 5422

Re: Max tx length of spi_transaction_t?

As far as I can see, if using spi_master driver, the size of the transaction transmit buffer is limited only by the amount of free heap (or stack, if you allocate the buffer on the stack).
by loboris
Wed Mar 08, 2017 7:59 am
Forum: ESP32 IDF
Topic: SPI transmission repetition rate
Replies: 7
Views: 4912

Re: SPI transmission repetition rate

Once the spi bus is initialized, the device added and the device initialized (you can call spi_device_transmit for that), you no longer need to use queued/DMA data transfer. You can add the simple functions for non-queued/no-DMA data transfer to spi_master driver: static void IRAM_ATTR spi_transfer_...
by loboris
Sat Mar 04, 2017 10:45 am
Forum: General Discussion
Topic: ESP-WROOM-32 and battery-backed RTC?
Replies: 5
Views: 7045

Re: ESP-WROOM-32 and battery-backed RTC?

There are many LDOs with ultra low quiescent current ( < 2uA ) and also step-down regulators with even lower quiescent current which can be used, so there's actually no need for separate RTC battery. TPS62743(1) for example has less than 1 uA quiescent current with 90% efficiency at <10uA load so hi...

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