[ What is SimmStick ] News ] Contest ] Entries ] SimmStick PCB's Motherboard ] SimmStick PCB's Atmel ] SimmStick PCB's PIC ] SimmStick PCB's Miscelanea ]



Simmstick Overview

SimmStick™ is a 30 pin simm socket based Single Board Computer designed by Antti Lukats from Estonia that has started with the PIC16Cxx chips and is now migrating to other Microcontroller families such as the Atmel devices. There are now Atmel AVR and non-AVR support boards for both 20 and 40 pin micros. The simm socket used is the common 30 pin one used for many years on PC motherboards.

Small and large proto boards, CPU boards, Motherboards, and many I/O boards are under design. Custom or third party boards are encouraged. DonTronics now has many new board designs available. These include Relay modules, LEDs and Switches I/O boards, and two new motherboards.

Boards are re-usable and reconfigurable for many different applications. You can prototype a design on a breadboard with a 30 pin Simm Socket for your PIC16Cxx or Atmel micro, then a final board design can include or exclude the SimmStick module.

The DonTronics DT001 8 slot Development Platform also contains an inexpensive PIC programmer for the SimmStick bus. A SimmStick bus structure isn't a definite requirement as these modules can also be connected together with straight or right angle 30 pin male and female pins, as a set of header pin holes are provided just behind the edge connector pads.

Specific Questions:

What are the 3 special I/O lines used for?
A1, A2, and A3 are User defined. They can be a card select, Video In/Out, whatever you care to make it for your project.
We have used it for alternative RS-232 on some boards.

Why connect D0 to D15 together on the motherboards?
Most small applications may only have 2, 3, or 4 boards connected together. In these cases, the I/O will no doubt be common.

On larger applications, or where multi-processors are used, you may need to custom design or jumper a motherboard to suit. The idea is to change the mother board platform to configure your SimmSticks. The most common hobby PCB board you can purchase appears to be a simple parallel tracked PCB that matches 30 pin Simm sockets nicely.

If you need to design and manufacture a custom motherboard and use off the shelf SimmSticks, then future design is easy. You don't need to cut tracks and run jumpers on SimmSticks if you do all your configuration on the motherboard.

Physical specifications for SimmStick are shown below.

An Internet Based Distributor network has been setup for SimmStick and our support page has further information.





1 A1 Special IO 
2 A2 Special IO 
3 A3 Special IO or Negative Supply
4 PWR Unregulated DC (VPP) 7.5V to 18V DC
5 CI/A4 Clock Input or OSC1 (Note 1)
6 CO/A5 Clock Output or OSC2 (Note 1)
7 VDD +5V In or Out +/- 5%
8 RES Reset In or Out Active low
9 GND Digital Ground
10 SCL I2C Clock or IO
11 SDA I2C Data or IO
12 SI Serial In or IO
13 SO Serial Out or IO
14 IO/A6 General purpose IO
15 D0 IO
16 D1 IO
17 D2 IO
18 D3 IO
19 D4 IO
20 D5 IO/MOSI or SPI Master Out Slave In (Note 2)
21 D6 IO/MISO or SPI Master In Slave Out (Note 2)
22 D7 IO/SCK or SPI Clock (Note 2)
23 D8 IO
24 D9 IO
25 D10 IO
26 D11 IO
27 D12 IO
28 D13 IO
29 D14 IO
30 D15 IO

Note 1 ***
We feel the most misused, abused, and never used pins are the clock lines. Should never have come out at all. The guru did make a mistake here. As we redesign boards, we will remove these tracks, but it could be years now of course before it filters through. Have added the alternative pin designations A4 and A5. Scenix Micros use the clock lines for programming, so these may need to be routed via the "A" lines or perhaps a programming header.

Note 2 ***
For SPI Operation, an additional I/O is required for the Chip Select of each SPI Device.

 SimmStick Dimensions

The 30 edge connector Pads are .07" wide by .08" long.The first set of holes back from this edge are .1" from the edge of the board and offset .05" to the right.

A DT Series Board 2 Inch Simmstick is 2.025" high and has the top holes .175" from the top edge.
The spacing is the same from each edge, that is .13"
A DT Series Board 2.5 Inch Simmstick is 2.65" high and has the top holes .175" from the top edge.
The spacing is the same from each edge, that is .13"


[ What is SimmStick ] News ] Contest ] Entries ] SimmStick PCB's Motherboard ] SimmStick PCB's Atmel ] SimmStick PCB's PIC ] SimmStick PCB's Miscelanea ]

Page up-dated at September 18st, 2000

homeHome Cards Categorical Index Digital I/O Hobby