without any external wiring.
This patch introduces the new method
Esp.rebootIntoUartDownloadMode()
When the user calls this method the ESP8266 reboots into the UART
download mode. In this mode the user can use esptool.py to flash a new
firmware file. The following command was used to test it:
$ esptool.py --before no_reset --after soft_reset --chip esp8266 \
--port /dev/ttyUSB0 --baud 460800 write_flash 0x0 firmware.bin
The implementation is based on the original implementation in the
boot ROM. Some parts of the original implementation can be found in
[1]. This patch is a squashed and simplified version of [2]. The non
squashed version might be helpful in case of debugging issues.
[1] https://github.com/twischer/xtensa-subjects/blob/master/reversed/bootrom.c
[2] https://github.com/twischer/Arduino/tree/reboot_uart_download_full
Signed-off-by: Timo Wischer <twischer@freenet.de>
This commit allows switching SDK firmware:
nonos-sdk-pre-v3 shipped with release 2.5.0 has issues:
* Some boards show erratic behavior (radio connection is quickly lost), with an unknown cause.
These boards work well with previous nonos-sdk-2.2.1 firmware (#5736)
* Overall performances seem to have decreased (#5513)
This PR restores sdk2.2.1 (as in core-2.4.2).
SDK-pre-3.0 - which has brought long awaited fixes (WiFi sleep modes) - is still available through a menu option available only with generic board.
BREAKING
* new define `-DNONOSDK221=1` or `-DNONOSDK3V0=1`
* for external build systems: new library directory: `tools/sdk/lib/<version>/lib`
* PIO: variable `PIO_FRAMEWORK_ARDUINO_ESPRESSIF_SDK3` is needed for sdk-pre-v3.
Fix#5736
