[NTLK] What we want on Internal Newton Extension Module by PCBMan :)
m.melcher at robowerk.de
Wed Dec 29 08:36:51 PST 2021
Hi PCBMan and friends,
for a while I was trying to build this form modules, but gave up because my electronics knowledge is too little, especially in building a correct power supply and not destroying original MessagePads.
My functionality was:
- USB-C connector
* power over USB (DC/DC stebdown to 7.2V with power limiter)
* charging over USB (USB-C can provide much more than 5V)
* data over USB-C to serial port
- ESP32 wifi/BT module
* connects over the Modem port and pretends to be an actual modem
which makes it usable without preadding any software
* user can choose to connects BT to sound(?), serial, or keyboard port
* ESP connects to a MicroSD Card, accessible through the rear opening
can be used to access a local copy of Unna
can be used to update software in this module
- Power control for this module
Alternatively, there is a ESP32 module that has a builtin USB connection, but no BT.
Central chip to connect everything was an Altera MAX 3000 (EPM3032). This chip is a programmable logic chip that also takes care of 3.2V vs. 5V signalling. It can be reprogrammed by the ESP, so the module can freely reconfigure itself as we upgrade software.
I'll be happy to provide more details as needed. I would also program the ESP to behave like a modem to connect to Wifi networks or the internal SDCard.
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