nuttx/boards/xtensa/esp32/esp32-wrover-kit/README.txt
Pedro Bertoleti a4f422a801 This commit enables BMP180 suport for ESP32.
As ESP32 has 2 I2C interfaces and BMP180 is a I2C sensor, the criterias to use BMP180 in I2C0 or I2C1 are:

1- First, bring-up routines search for BMP180 in I2C0.
   If BMP180 is found in I2C0, then /dev/press0 is created.
2- If BMP180 cannot be registered in I2C0, bring-up routines search for it in I2C1.
   If BMP180 is found in I2C1, then /dev/press0 is created.

It means only one BMP180 could be suported in Nuttx. In my tests I've observed
that BMP180 example application doesn't seem to work with /dev/press1 BMP180 device,
therefore even BMP180 is found in I2C1, it'll be registered as /dev/press0 device.
2021-02-22 21:45:16 -03:00

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README for the Espressif ESP Wrover Kit
==============================================
The ESP32 is a dual-core system from Espressif with two Harvard
architecture Xtensa LX6 CPUs. All embedded memory, external memory and
peripherals are located on the data bus and/or the instruction bus of
these CPUs. With some minor exceptions, the address mapping of two CPUs
is symmetric, meaning they use the same addresses to access the same
memory. Multiple peripherals in the system can access embedded memory via
DMA.
ESP-WROVER-KIT is an ESP32-based development board produced by Espressif.
ESP-WROVER-KIT features the following integrated components:
ESP32-WROVER-B module
LCD screen
MicroSD card slot
Its another distinguishing feature is the embedded FTDI FT2232HL chip,
an advanced multi-interface USB bridge. This chip enables to use JTAG
for direct debugging of ESP32 through the USB interface without a separate
JTAG debugger. ESP-WROVER-KIT makes development convenient, easy, and
cost-effective.
Most of the ESP32 I/O pins are broken out to the boards pin headers for easy access.
Buttons and LEDs
================
Buttons
-------
There are two buttons labeled Boot and EN. The EN button is not available
to software. It pulls the chip enable line that doubles as a reset line.
The BOOT button is connected to IO0. On reset it is used as a strapping
pin to determine whether the chip boots normally or into the serial
bootloader. After reset, however, the BOOT button can be used for software
input.
LEDs
----
There are several on-board LEDs for that indicate the presence of power
and USB activity.
There is an RGB LED available for software.
Configurations
==============
nsh
---
Basic configuration to run the NuttShell (nsh).
wapi
___
This is a congiuration to test the Wifi driver using WAPI.
The Wifi passphrase and SSID can be configured from menuconfig, then once
booted you can check if an IP address was assigned:
nsh> ifconfig
If not configured at startup, you can connect to a network with the following:
wapi psk wlan0 mypassword 1
wapi essid wlan0 myssid 1
gpio
---
This is a test for the GPIO driver. It includes the 3 LEDs and one,
arbitrary, GPIO. For this example, GPIO22 was used.
At the nsh, we can turn LEDs on and off with the following.
nsh> gpio -o 1 /dev/gpout0
nsh> gpio -o 0 /dev/gpout1
We can use the interrupt pin to send a signal when the interrupt fires:
nsh> gpio -w 14 /dev/gpint3
The pin is configured to as a rising edge interrupt, so after issuing the
above command, connect it to 3.3V.
Using QEMU:
==========
First follow the instructions at https://github.com/espressif/qemu/wiki to build QEMU.
Enable the ESP32_QEMU_IMAGE config found in "Board Selection -> ESP32 binary image for QEMU".
Download the bootloader and the partition table from https://github.com/espressif/esp-nuttx-bootloader/releases
and place them in a directory, say ../esp-bins.
Build and generate the QEMU image: `make ESPTOOL_BINDIR=../esp-bins`
A new image "esp32_qemu_image.bin" will be created. It can be run as:
~/PATH_TO_QEMU/qemu/build/xtensa-softmmu/qemu-system-xtensa -nographic \
-machine esp32 \
-drive file=esp32_qemu_image.bin,if=mtd,format=raw
External devices:
=================
BMP180
------
When using BMP180 (enabling CONFIG_SENSORS_BMP180), it's expected this device is wired to I2C0 bus.
The current bring-up routines doesn't allow BMP180 device to be used in I2C1 bus.