Search found 14 matches

by chopin1998
Wed Sep 06, 2023 5:54 am
Forum: 硬件问题讨论
Topic: ESP32-S2FN4R2 内置Flash和PSRAM时, VDD_SPI怎么接?
Replies: 1
Views: 18959

ESP32-S2FN4R2 内置Flash和PSRAM时, VDD_SPI怎么接?

看文档, 此时应该使用 主电源输入配合芯片内部的一个 Rspi, 那么 VDD_SPI 只要接一个电容到地就可以了吗? RSPI的作用什么?
by chopin1998
Mon Jun 05, 2023 2:44 pm
Forum: 硬件问题讨论
Topic: 想确认一下 esp32 s2 支持 gc032a 摄像头, 对吗?
Replies: 1
Views: 2233

想确认一下 esp32 s2 支持 gc032a 摄像头, 对吗?

看规格应该可以, 但是想最终确认一下
by chopin1998
Wed May 10, 2017 9:21 am
Forum: General Discussion
Topic: can I use esp32 as a bluetooth TAG, and limit esp32 tx range in 0.5m?
Replies: 0
Views: 3325

can I use esp32 as a bluetooth TAG, and limit esp32 tx range in 0.5m?

这个可以被实现吗?

Could it be implemented?
by chopin1998
Thu Mar 23, 2017 3:58 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 17631

Re: only three slave can be attached in SPI ?

Ooops.... I can set spics_io_num = -1, but when I call spi_bus_add_device > 3 times, driver still said E (199) spi_master: spi_bus_add_device(326): no free cs pins for host .... If you wan to use more than 3 devices, you have to modify spi_bus_add_device() function, something like this: #define NO_...
by chopin1998
Wed Mar 22, 2017 6:53 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 17631

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 chopin1998
Tue Mar 21, 2017 9:01 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 17631

Re: only three slave can be attached in SPI ?

yeah, i did this and use .pre_cb and .post_cb to tgl CS pin

thank you!
by chopin1998
Tue Mar 21, 2017 3:08 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 17631

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?
by chopin1998
Tue Mar 21, 2017 3:01 am
Forum: General Discussion
Topic: only three slave can be attached in SPI ?
Replies: 8
Views: 17631

only three slave can be attached in SPI ?

i have layouted a PCB, esp32 connect 5 spi slave, share same CLK/ MISO/ MOSI and 5 independent nCS to every device. but when I use spi_bus_add_device() 5 times, it said: E (199) spi_master: spi_bus_add_device(326): no free cs pins for host E (199) spi_master: spi_bus_add_device(326): no free cs pins...
by chopin1998
Fri Jan 13, 2017 7:30 am
Forum: Hardware
Topic: External Interrupt Latency
Replies: 17
Views: 36981

Re: External Interrupt Latency

I have done a measurement and delay from external trigger to application-provided ISR handler is around 2us (at 240MHz clock), which is around 500 cycles. yes, real interrupt delay is about 1.7~1.8uS, it seems too long for a 240Mhz processor, I measure the delay on a 32Mhz 8bit mcu, delay is ~700nS...