Compatibility with ESP8684 WROOM-01C-H2

[anarsoul]

I've recently purchased come ESP8684 WROOM-01C-H2 [1] and tested its compatibility with AY-WiFi.

While it's pin-compatible with ESP12E, it requires rebuilding esp-at firmware to use UART with TX on GPIO20, RX on GPIO19, CTS on GPIO6, RTS on GPIO7, diff:

diff --git a/components/customized_partitions/raw_data/factory_param/factory_param_data.csv b/components/customized_partitions/raw_data/factory_param/factory_param_data.csv
index c56f2d01..3104dfb6 100644
--- a/components/customized_partitions/raw_data/factory_param/factory_param_data.csv
+++ b/components/customized_partitions/raw_data/factory_param/factory_param_data.csv
@@ -9,5 +9,5 @@ PLATFORM_ESP32,ESP32-D2WD,"2MB flash, No OTA",4,78,1,1,13,CN,115200,22,19,15,14
 PLATFORM_ESP32C3,MINI-1,TX:7 RX:6,4,78,1,1,13,CN,115200,7,6,5,4
 PLATFORM_ESP32C3,ESP32C3-SPI,,4,78,-1,1,13,CN,-1,-1,-1,-1,-1
 PLATFORM_ESP32C3,ESP32C3_RAINMAKER,TX:7 RX:6,4,78,1,1,13,CN,115200,7,6,5,4
-PLATFORM_ESP32C2,ESP32C2-2MB,"ESP32C2 (ESP8684) series with 2MB flash, TX:7 RX:6",4,78,1,1,13,CN,115200,7,6,19,20
+PLATFORM_ESP32C2,ESP32C2-2MB,"ESP32C2 (ESP8684) series with 2MB flash, TX:20 RX:19",4,78,1,1,13,CN,115200,20,19,6,7^M
 PLATFORM_ESP32C2,ESP32C2-4MB,"ESP32C2 (ESP8684) series with 4MB flash, TX:7 RX:6",4,78,1,1,13,CN,115200,7,6,5,4

Also TX drive strength is not enough to bring AY internal pull-up to 0V:

So I replaced R1 with an emitter follower (just a BC557 transistor), base goes to ESP TX, emitter to pin header, collector to GND, results looks like this and works fine:

[1] https://www.aliexpress.com/item/1005006250229794.html

[UzixLS]

Next PCB revision will receive 74LVC2G34GW buffers for reliable level translation and TX driving.