Hey guys, Chris again from Core Electronics. This is the expansion board 2.0 from PyCom, you put it underneath you PyCom microcontrollers and it gives you some basic inputs and outputs.

Let's have a look at the bench and we'll see here that a PyCom microcontroller, any of them will go straight into a breadboard. That's great, all you really need to do is at the top here provide power and that's in the range of 3.3 to 5.5 volts and by default, your microcontroller will create a wireless access point, which you can join and then program it using Telnet and FTP. It's important to note there that there's no reverse bias protection on that power socket, so if you get the polarity wrong you'll do damage. Also, the pins are not 5 volt tolerant, so make sure that you're only using the 3.3 volts, which is supplied out of the third pin to do any peripherals that come back into the microcontroller.

If you decide you want to have a serial connection to the PC, you would normally add an FTDI board. This one here has a voltage selector between 5 or 3.3 volts make sure you select the 3.3 volts, and everything will be fine. Alright, now let's have a look at the expansion board, here it is if I turn up the right way. On the expansion board we first have, a socket in the middle which takes your microcontroller all the microcontrollers fit from the PyCom range and they fit backwards if you want to. When I say if you want to don't do that that will do them damage. Make sure you connect them the right way around, which is having the LED at the top at the same end as the USB socket. So, that's the inside row of female pin headers there, the outside row of pin headers is space for you to add jumper leads to a breadboard. If you're prototyping or if you built a circuit that has pin headers you can drop them straight on there. The USB port at the top obviously is used for power and communications, there's a built-in FTDI chip so a serial connection with the microcontroller is created just by dropping it on the expansion board. So, you have two ways you can connect.

Here we have a battery port where we can connect a standard lithium ion or lithium polymer cell. Some good features of that, there's a power multiplexer, so if either of these power sources is connected or indeed if you just go straight on to the pin headers, whichever power source is available will be selected to power the project. If two sources are available in one of them is the battery, then the battery will be charged automatically and so as you change your power sources around there'll be no dropouts in power.

There are a couple of LEDs down the right-hand side of the board here, there's one called USB which lights up when the USB has power on, another one has CHG which is charging the battery and there's a user configurable LED and BUTTON, as an output and an input.

At the bottom here, we have a standard micro SD slot, micro SD is obviously having to be formatted with FAT16 or FAT32 and I think there's a 16GB limit there. On the left is a set of jumpers, which allow you to disconnect any of the default configuration of the board, so you can have it configure your own way. If you have a look at the pin out diagram on the PC with me, you can see in the top right of the board, there are red and black connectors there for voltage in. The 3.3 v which is shown in red is a 3.3-volt rail that comes from a regulator on the microcontroller, so if there's no micro control to fit it there's no 3.3 volt on that pin. There are some light blue tags there four of them are labelled FTDI and three of them are labelled SD something. So, obviously the FTDI is for communicating back to the PC that's on the USB, SD obviously connects to the SD socket at the bottom.

If you want to disconnect either of those features, sorry I don't think you can connect disconnect the SD card, but the jumpers, the top four jumpers as shown in the bottom left of the diagram, down here the top four jumpers allowed to disconnect that FTDI. So, if you want to use both serial ports that are available on the microprocessor you can do that and disconnect the one from the USB.

The yellow tags there on the left, show that when the reset is pushed on the microcontroller that that can be used to reset slave devices of GPS or whatever. On the bottom left is an LED and button label there, so they connect obviously to the LED and button that are on the board and on the right hand side this VBATT and below it is of the voltage divider circuit so the battery voltage, the raw battery voltage is divided down and made available at P16, as an analog input, so you can measure the battery voltage at any time.

The rest of those pin headers if we look again at the bottom there's a disconnector for the battery, so that the pin P16 can be connected to something else and isn't directly connected to the battery. Below that the user LED can be disconnected and at the bottom there you can see CHG, the charge rate on the battery can be either 100 or 450mA. The user button there doesn't have a disconnect, because it's a normally open contact and does nothing unless it's pressed.

Alright, so that's our overview of the expansion board 2.0 from PyCom, a beautiful little board that goes with all your PyCom microcontrollers, have a look for another video shortly we'll be putting up a getting started guide, which will show you some basic programming. Hit the link below for the documentation.

Thanks for watching, Coreelectronics.com.au