GenBoard/VerThree input channels
We need a lot of inputs if we wish to integrate lots of functions. 1-wire daughterboard might be a solution but GenBoard/VerThree has some unused pins which are used as digital inputs.
Easy connection and configuration of these input pins is IMPORTANT!
I think we can activate the AVR's pullup resistor on the specific pin (if it's an AVR pin), and connect a simple switch between this pin and ground. Activated state means that pin is grounded (on logic level 0).
Functions that require input channel
These 2-state simple inputs are needed for some driver-controllable functions. For example:
- AntiLagSystem (on/off switch on dashboard)
- NitrousController (on/off switch on dashboard)
- LaunchControl (on/off switch on dashboard and another for the clutch sensor)
- RaceShifter (gearshifter motion sensor, or manually activated button on the shifter)
- etc.
Problem
- The number of the usable inputs of the AVR is very limited (GenBoard/VerThree only has about 2 times more inputs than required to run an engine injection and ignition, while it has 5x more outputs. Maybe changing in 4.x? )
- Also if you wish to use some of them, (in 3.x) you need to use wires to the connector outputs in the box.
- Also you must specify your own wiring standard to the EconoSeal III connectors.
EC pin candidates
Fortunately, the number of connector pins is far enough, because most people doesn't use
- 8 injector channels and
- 8 coil channel power outputs
- secondary WBO2 pins (nernst is a natural input signal)
- stepper outputs seems also good choice
if you don't want to use them for their original function.
You could use the
- currently unassigned pin 14 and pin 15 on the EC18 connector at first see (we usually use it for RS232 TX, RX).
available signals on the board
I've found only the following pins to use as digital inputs:
- SCL (PD0) - on JP1 connector
- SDA (PD1) - on JP1 connector (current default for AntiLagSystem)
and, if you always prefer the BootLoader instead of ISP cable, you can use (on JP_ISPI connector):
- SS (PB0)
- SCK (PB1)
- MOSI (PB2)
- MISO (PB3)
- 8 inputs from MCP3208 (max 12 bit ADC, but usable for digital input as well). Some of them even has pullup. Some are available on the EC18. Some are easy to make very sensitive (a few mV), or differential input or both (with midOPA)
[resistor network to connect several digital switches to an analog output]
![[resistor network to connect several digital switches to an analog output]](http://www.vems.hu/files/DaveBrul/switch_interface_idea.JPG){kind=link}
Someone can write here any other possible pins?
(hackish) Here is what I think. The easiest and most versatile way to do it would be to get the 1wire thing working. Then an infinite number of inputs could be added. Maybe someone can find some switches that already talk the 1wire protocol... whatever that is. Having installed a large number of competing standalones in a variety of cars I'm often frustrated by the need to have 1-2 more switches for something odd the owner dreams up. Launch control (could be triggered from the VSS sensor), water injection pressure input, nitrous pressure/temp sensors, high boost switch, boost knob (adjustable), race gas switch, clutch switch are all inputs I've been asked for.
Discussion
Write other ideas here regarding to PCB and GenBoard/FirmWare modifications.