I have been meaning to do several microcontroller based projects for some time now. Ideally I wanted to do it without spending any money so I decided to make myself a PIC programmer with some samples from Microchip. This would also make the process more interesting.

The plan was to make a usbpicprog and bootstrap it with a serial port based programmer using an old computer. I bought all the parts, including copper clad board and ferric chloride but never quite got round to doing it. This was in part because I was not very keen to have to work with ferric chloride and I didn’t want to dissolve the sink.

Meanwhile, I had been hearing about the Arduino more and more. Initially I ignored it as something for artists and people who didn’t know what they were doing. I had spent some time at university learning about and using real microcontrollers with none of this boot loader nonsense so I did not think I needed such things. Then I realised that being leet enough not to require simplification did not make quicker development a bad thing. :-) I decided I had wasted enough time and just wanted to get something done, so I bought an Arduino.

I actually chose the seeedunio, an Arduino clone. The design is open so this is allowed and in fact there are some improvements made in the seeeduino. Primarily I chose it though because it was the cheapest. I still don’t like the idea of paying decapounds for a single basic microcontroller and some soldering. I also ordered an ethernet shield, which is what an expansion card is called in the Arduino world. These arrived yesterday.

It took me longer than I would have liked to get started, with the blinking LED hello world of microcontrollers, because there were no instructions about the correct settings. After some googling and trial and error I determined that I had to set the reset switch on the board to auto and, in the Arduino IDE, set the board type to Deumilanove or Nano w/ ATmega328. After that I very quickly had it beaconing my callsign on the board mounted LED attached to pin 13. So far quite reasonable.

Then I decided to plug in the ethernet board and run the example programs. I had to stick all the source files in the same directory and change the ip address and then I was pinging the board. It took only a few minutes. This I thought was pretty ridiculous. Then I used the web server program. It worked. I couldn’t really believe this - this did not seem like electronics at all. I would expect this to have taken weeks of debugging, loose wires, errors in PCB design, software bugs and frustration but here it was working in a few minutes with no test gear in sight. I have certainly confirmed my get things done faster conjecture.

It was not quite as good though when I wanted to connect stuff up to it. The board did not come with a data sheet and I could not find much at all online. In the end I went to Atmel’s web site and downloaded the datasheet for the ATmega328P on my board. Included below are some useful figures from it.

Reference

Seeeduino - Summary of Initial Setup

I am using the Seeeduino V2.21 which is also marked ARD128D2P.

It uses the ATmega328P.

This is the error I got initially:

avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x00

The solution:

• Move reset switch to auto
• Set board type to Deumilanove or Nano w/ ATmega328.

ATmega328P Data

Absolute Maximums

Operating Temperature	-55°C to +125°C
Voltage on any Pin except RESET with respect to Ground	-0.5V to VCC+0.5V
Maximum Operating Voltage	6.0V
DC Current per I/O Pin	40.0mA
DC Current VCC and GND Pins	200.0mA

Programming

The Arduino environment uses C but with some magic, see Arduino Build Process.

Ethernet board

It’s ENC28J60 based. This is not the same as the official one, which uses the Wiznet W5100.

Bought from ekitszone. Looks well made and works.