WiFi for the Colour Maximite 2

Fitting it

Switch the CMM2 off, then push the module's socket onto the rear I/O header so that the module stands upright behind the computer.

• On a G2 or a G3, fit it with the words THIS WAY UP on the board at the top.
• On a G1, fit it upside down, with THIS WAY UP at the bottom. The G1's I/O header has its pinout rotated 180 degrees compared with the G2's, so turning the module over puts every pin in the right place.

The pins it uses

These four pins aren't connected on the module's pass-through header. Pin 35, SPI2's input, isn't used, and passes through as an ordinary I/O pin.

When WiFi is on, SPI2 and these four pins belong to the radio, and the SPI2 commands and SETPIN on those pins give an error. Without OPTION WIFI the firmware leaves them alone, although with the module fitted they're still wired to it.

Using it

Support comes with MMBasic V8.00.00 for the CMM2, starting with its first beta, and WiFi has been confirmed working on the G1, the G2 and the G3. The networking is the PicoMite WebMite's, ported to the CMM2 as it is, so the commands work as they do on a Pico W and they're documented in the PicoMite User Manual. Programs written for a WebMite should carry over with little or no change.

Joining a network

Give the CMM2 your network's name and password once, at the command prompt:

OPTION WIFI "MyNetwork", "MyPassword"

The CMM2 restarts and joins the network in the background, which takes about 7 seconds, without holding up the prompt. It joins again every time it's switched on. Optional extra arguments set a host name (by default PICO followed by the board's ID), a fixed IP address with its mask and gateway, and a country code. Then:

PRINT MM.INFO(IP ADDRESS)   ' the address the network gave it
WEB PING "mather.host"      ' check it can reach the internet
WEB NTP 0                   ' set the clock from the internet, in UTC

WEB NTP sets the CMM2's clock, and its real-time clock too if one is fitted. Its argument is your time zone's offset from UTC in hours.

What it can do

A small web server

Set the port once with OPTION TCP SERVER PORT 80, then run this. A browser pointed at the CMM2's address gets a page showing its date and time: WEB TRANSMIT PAGE fills in each {expression} in the page as it sends it.

Dim buff%(512)
Open "A:/index.html" For Output As #1
Print #1, "<html><body><h1>Colour Maximite 2</h1>"
Print #1, "<p>{Date$} {Time$}</p></body></html>"
Close #1
Print "Serving at "; MM.Info(IP ADDRESS)
WEB TCP INTERRUPT webreq
Do : Loop

Sub webreq
  Local a
  For a = 1 To MM.Info(MAX CONNECTIONS)
    WEB TCP READ a, buff%()
    If LLen(buff%()) Then WEB TRANSMIT PAGE a, "A:/index.html"
  Next a
End Sub

How fast it is

The transfer and HTTPS figures came from a test program driving the network directly; MMBasic programs add their own overheads.

Good to know

• Memory: with OPTION WIFI set, the firmware sets aside 128 KB of memory for the network. Without it nothing is taken. On a G1 the 128 KB comes from the top of the display memory, so with WiFi on some screen modes have one page fewer: 1024 × 768 in 16-bit colour (MODE 9,16) has one page instead of two, for example. Loadable programs on a G1 still get all of the display memory, and WiFi reconnects when they end.
• No SD card needed: the radio's own firmware and the network code are built into the CMM2's flash.
• Without the module: if OPTION WIFI is set but the module isn't fitted, the CMM2 says WiFi module not found at start-up and carries on as normal, with the memory and pins free. The settings are kept for when the module goes back on.
• Loadable programs: while a loadable program such as an emulator or MicroPython is running, the network isn't looked after, so connections may drop.
• Range: the module sits behind the computer, so a metal case or rear panel will cut its range.
• Bluetooth: the radio has Bluetooth too, but the firmware doesn't use it yet.