All of this work on the internal serial slot is in support of my WiFi module project. The goal is to build an internal interface to a ConnectOne WiReach module. I like this module for a few reasons:
- It supports modern wireless networking, such as WPA2. There isn’t any native way for the Newton to connect to a modern WiFi network, and likely there never will be.
- It supports a PPP server. This means that the module can appear to Newton Internet Enabler (NIE) as a PPP dialup server. In effect, you can “dial up” to a wifi network.
- It supports an AT command set for configuration– so you can send a few commands from PT-100 or using the script utility in NIE to configure the module.
I’ve done some testing today and found that it works really well. A few caveats:
- The Newton’s internal 3.3v regulator is not sufficient to run the module. This was expected, but it does mean that any design will have to have a 3.3v regulator that runs off of the battery supply lines. Luckily the internal serial slot does provide access directly to the battery.
- Hardware flow control seems to work. I have a history of messing up the pinout, so I’l probably have a solder jumper that you can cut if you want to disable hardware flow control.
- There’s a giant capacitor right where I would want the module to sit. I think that that there is enough clearance in the area, but I’m starting to be concerned about how this will all fit.
My current thinking is to use the SerPortSel3 line to control the 3.3v regulator shutdown. Serial3 is just as fast as Serial0 (even though the specs say that Ser3 is slower, this doesn’t appear to be the case, it works fine at 119200) I wouldn’t want the module running all the time, drawing power. SerPortSel3 would work to turn on and off power to the module. Since no one ever connects anything to Serial3 externally, I am thinking that I might skip a tri-state bus buffer.