add miniesptool for nina fw

Author: brentru

examples/miniesptool_esp32nina.py

@@ -0,0 +1,28 @@
+import time
+import board
+import busio
+from digitalio import DigitalInOut, Direction # pylint: disable=unused-import
+import adafruit_miniesptool
+
+print("ESP32 Nina-FW")
+
+uart = busio.UART(board.TX, board.RX, baudrate=115200, timeout=1)
+resetpin = DigitalInOut(board.D5)
+gpio0pin = DigitalInOut(board.D6)
+
+esptool = adafruit_miniesptool.miniesptool(uart, gpio0pin, resetpin,
+                                           flashsize=4*1024*1024)
+esptool.sync()
+
+print("Synced")
+print("Found:", esptool.chip_name)
+if esptool.chip_name != "ESP32":
+    raise RuntimeError("This example is for ESP32 only")
+esptool.baudrate = 912600
+print("MAC ADDR: ", [hex(i) for i in esptool.mac_addr])
+
+# Note: Make sure to use the LATEST nina-fw binary release!
+esptool.flash_file("ninafw.bin")
+
+esptool.reset()
+time.sleep(0.5)