ETT boards : AVR Stamp

On the right is the ET AVR Stamp processor module. Take a look at it. In the Multimedia section (bottom of page) is a link to a high res picture. For now I will deal with the small picture. It shows:

A 42 x 65 mm module
2 x 25 pins in DIP format in 1500 mil spacing
All I/O pins brought to the outside
ISP header
Power Good LED
Vref potentiometer for onchip ADC
ATMeaga 128 processor with 16 MHz Xtal
Reset button
Lots of decoupling capacitors

When the board arrived it was clear that this was a good deal. The board is nicely made. It is most probably hand soldered, but by trained technicians who took the time to get the job done. The boards are better soldered than the Olimex boards from Bulgaria. Apparently Bulgarian wages are moving towards the normal EU levels.
Board design and PCB layout are excellent. All PCB traces have 45 degree corners. Lot's of silkscreen texts to illuminate the most obvious parts and functions. All in all: good show, old chap!

I bought this board from Futurlec and it cost me €15

Ready built. If I have to buy the parts in Europe it would have cost me more.

When I wanted to get using the board, I found out I was too soon in ordering the lot. The board is hard to use as is. It must be mounted in a dedicated controller or on the accompanying ETT development board (on the right). This is some kind of motherboard and the AVR Stamp can be plugged into two female headers on the right side of the board. So I decided to order this motherboard as well.

The ET-AVR Stamp motherboard has it all:

Accepts 7 - 12 Volts AC or DC to make 5 Volts onboard
On board TTL to RS232 converter (MAX 232)
Socket for connecting a text LCD module (with contrast control)
Big prototyping area with power and ground rails
Breadboard module with self adhesive backside
Four LED's with 560 Ohm series resistor
One piezo buzzer with buffer transistor
JTAG interface connector
Four switches with pull up resistors
Four 10k potentiometers connected between +5V and Ground (for testing the ADC)
Two sets of four elevated posts, each for accepting one ETT miniboard
A very well made, double sided, fully masked, printed circuit board of 90 x 150 mm

This board set me back €20 at Futurlec

Again: you cannot make it yourself for this kind of money. And I see it as a kind of development aid. The fine people at ETT are now encouraged to keep making this kind of products.

Below is an extra picture of the Motherboard with the functions in highlight.

On the right you see the AVR Stamp Motherboard, with the AVR Stamp processor module installed and two (randomly chosen) ETT miniboards mounted. This picture already shows more detail than the previous pictures shown above. The board in top is the 'Stepper mini' board. The lower board is the (not necessary) TTL to RS232 converter, whioch of course is already on the motherboard.

The Stepper Miniboard is a very nice board. It has a small steppper motor with an arrow attached to its shaft. The challenge now is to have the arm rotate in a controlled way. The board has buffer transistors on each motorcoil as wel as LED indicators. Plus a big (1A) recoil diode per motorwinding. This is a very fine board with positive feedback for the programmer.

ETT supply a lot of miniboards, among which are:

MP3, Audio
DAC
DC-motor, Steppermotor boards
Serial out, I2C
Flash card, SD card
Switch mode power supplies (using the LM 2575 regs)
Relay, opto isolator, 7 segment LED
Logic level translator

The initial setup will be to have the AVR Stamp mounted on its motherboard without any miniboards mounted. This way I can get familiar with both boards. Just connect the buzzer, a few LED's, a pot connected to an ADC input and a switch to a pin and see if I can things running. In fact, this is the only setup you need when you want to get started in programming: the Stamp and it's mother.

High resolution picture of full stamp board: p9290010.jpg.

High resolution picture of ET AVR Stamp processor module: p9300054.jpg.

Page created on 29 September 2008 and

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