Expose handler for BSSID, and wi-fi scan handlers for BSSID & channel.

[anecdata]

Changes to esp32spi.py to address #74

I'd appreciate @adafruit/circuitpythonlibrarians (don't seem to be able to tag the team) code review (and test). There were good examples in the code to work from, but first time interpreting C types into CP.

Tested on a variety of combinations of M4 and ESP32 hardware. I'll post a test code.py and sample output in the comments.

P.S. BSSID, like MAC, comes in with the first octet in the 6th byte. Depending on the resolution of #66 a helper function could be added or it could be left to examples to illustrate this.

[anecdata]

A tl;dr test code.py (assuming ESP32 is behaving):

import board
import time
from digitalio import DigitalInOut
from adafruit_esp32spi import adafruit_esp32spi
from secrets import secrets

spi = board.SPI()
try:  # PyPortal, etc.
    esp32_cs = DigitalInOut(board.ESP_CS)
    esp32_ready = DigitalInOut(board.ESP_BUSY)
    esp32_reset = DigitalInOut(board.ESP_RESET)
except AttributeError:  # Airlift FeatherWing & Bitsy Add-On compatible
    esp32_cs = DigitalInOut(board.D13)
    esp32_ready = DigitalInOut(board.D11)
    esp32_reset = DigitalInOut(board.D12)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

print('Connect...  BSSID     RSSI SSID')
esp.connect_AP(secrets['ssid'], secrets['password'])
# NEW: bssid
print('{5:02X}:{4:02X}:{3:02X}:{2:02X}:{1:02X}:{0:02X}'.format(*esp.bssid), end='')
print('     {: 4d} {:s}'.format(esp.rssi, str(esp.ssid, 'utf-8')), end='')
print(' ping=%dms (LAN)' % esp.ping(esp.network_data['gateway']))
print()

while True:
    print('Scanning... BSSID  Ch RSSI SSID')
    for ap in esp.scan_networks():
        # NEW: bssid, channel
        print('{5:02X}:{4:02X}:{3:02X}:{2:02X}:{1:02X}:{0:02X}'.format(*ap['bssid']), end='')
        print(' {: 3d} {: 4d} {:s}'.format(ap['channel'], ap['rssi'], str(ap['ssid'], 'utf-8')))
    print()
    time.sleep(10)

A more robust code.py is here.

Actual output data matches data from macos airport -s utility.
Sample output data has been munged for privacy:

code.py output:

ESP Firmware:   1.2.2.
ESP Status:     0
Connecting...   3
            BSSID     RSSI SSID
7C:D1:RE:DA:CT:4A      -51 NotImplemented ping=0ms (LAN)

Scanning... BSSID  Ch RSSI SSID
7C:D1:RE:DA:CT:4A   6  -51 NotImplemented
60:F4:RE:DA:CT:4E   6  -62 NotImplemented
00:1A:RE:DA:CT:02  11  -63 None_optout
00:1A:RE:DA:CT:01  11  -64 Blinka
90:72:RE:DA:CT:18   6  -90 None_optout_nomap
00:1A:RE:DA:CT:82   1  -93 None_nomap
20:C9:RE:DA:CT:FA   6  -95 None_optout_nomap

Scanning... BSSID  Ch RSSI SSID
7C:D1:RE:DA:CT:4A   6  -50 NotImplemented
60:F4:RE:DA:CT:4E   6  -60 NotImplemented
00:1A:RE:DA:CT:01  11  -63 Blinka
00:1A:RE:DA:CT:02  11  -65 None_optout
90:72:RE:DA:CT:18   6  -92 None_optout_nomap
20:C9:RE:DA:CT:FA   6  -94 None_optout_nomap

[brentru]

@anecdata This are very useful methods - thanks for exposing it within ESP32SPI.

I successfully tested against your provided example code and verified against airport -s (not posting result code for privacy reasons).

I also tested against ESP32SPI simpletest since it runs a wifi scan to ensure it still works as-expected:

ESP32 SPI webclient test
ESP32 found and in idle mode
Firmware vers. bytearray(b'1.2.2\x00')
MAC addr: ['0x5d', '0xad', 'snip', '0x33', '0x4f', '0xc4']
	snip		RSSI: -53
	snip		RSSI: -62
	snip		RSSI: -66
	snip		RSSI: -71
	snip		RSSI: -71
	snip		RSSI: -72
	snip		RSSI: -76
	snip		RSSI: -81
	snip		RSSI: -81
	snip		RSSI: -90