With BETA kits hitting soon, it’s time to start going over the inputs, outputs, and general capabilities of the ECU. This is a quick and dirty post that will later get wrapped into proper reference documentation. Any questions? Post a comment below or ask on the forum!

ECU Board Overview – I/O

5x Analog Sensor Channels

  • S1 – IAT
  • S2 – TPS
  • S3 – MAP
  • S4 – Narrowband O2 (later support for Wideband O2)
  • S5 – Fuel Pressure Transducer (FPX)

All analog inputs are 0v to 5v. Do not exceed 5.0v.

Note: Any unused sensor channels may be configured as 5v digital in/out.

2x High-Current Output Drivers (Injectors, pumps, or relays)

High-current outputs (HCO) are able to drive electro-mechanical devices such as injectors, relays, pumps, or other motorized components.

  • 2x HCO driver channels (HCO1 and HCO2)
  • 6a 12v, each channel
  • Hardware PWM support on HCO1
  • Opto-isolated and Flyback protected

HCO1 Driver: HCO1 driver is intended for use with a fuel pump, and has hardware PWM (pulse width modulation) support. For applications that don’t require an actively managed fuel pump, this driver is instead suitable for use in a 2-injector arrangement, with possible future support for dual cylinder engines. Compatible with either a Hi-Z or Lo-Z injector. Both peak-and-hold, and saturation modes are supported.

HCO2 Driver: HC02 does not have PWM modulation support. Thus, only saturation mode is supported on this driver channel. It is intended for use with a Hi-Z saturation-type injector.

Alternatively, HCO2 can be used to switch relays, fuel lock-offs, or non-modulated pumps.

Status Indicator (Multi-color LED)

  • Breathing ECU on, engine off
  • Blinking Cranking detected
  • Pulsing Engine running
  • Pulsing Soft rev limit engaged
  • Pulsing Hard rev limit engaged

Timing Sensor Input, and CDI Output

I’ll circle back and provide more details regarding timing sensors. Also, the possibility of induction-based sensing for industrial style engines. And what you’ll need to know about the ECU’s optional external CDI interface as well. For now, most BETA participants won’t need to bother with these details.

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