First, the board is based on an 8-bit Freescale microcontroller that has 24 12-bit ADC channels, 10 timer channels, CAN, 2 SCIs, 2 SPIs, 2 IICs and more with a 24MHz bus speed. So there is room for expandability. This board has the CPU, CAN transceiver, power supply, and 4 VR conditioners with differential inputs all mounted on the board in SMDs. It has circuits for through hole components for 6 high current drivers, 6 low current drivers that can be configured as either inputs or outputs (default will be 3 inputs and 3 outputs), and 8 ADC conditioners. All of these go to a DB37 and the high current drivers have their own 12V and ground connections separate from the rest of the board. And all the CPU I/Os are routed to headers. There is also a small 1"x1" proto area.
The board communicates through an MS2 or Microsquirt running the MS2/Extra 3.x code and MS3 using the CAN bus. The ECU reads inputs from the board and writes to the board to activate outputs and the MS2/Extra features can take advantage of the board I/Os for things such as PWM idle, PWM boost control (with real hardware PWM), spare digital ports, barometric correction, a second O2 sensor, table switching, launch control, and N2O control. And all these I/Os are available in the MS2/Extra data log so even with data that is unused by the firmware, it is possible to do some post processing on the PC for things like wheel speed or VSS using the PWM inputs.
The intention was to make it a cheap yet flexible and complete enough board to appeal to those needing more I/Os. But there is a second board, which will be ready soon, with an RTC (real-time clock), 3-axis accelerometer, USB connection, an optional GPS module, and an SD card. There are also 8 more ADC circuits which can be used for generic analog inputs or for EGT measurements using optional dedicated EGT amplifier chips.
The idea with the SD card is that this would make it a 2-board standalone datalogger. Of course, the SD card can also be used with either MS2/Extra (on an MS2 or Microsquirt) or MS3 to datalog the ECU data on the SD card without needing a PC in the car in addition to all the data captured by the board itself from all the different I/Os. And even though MS3 already has an SD card, it might not be a bad thing to have 2 SD cards available with one dedicated to fast, critical data and the other to more complete but less time-critical data logged at a slower rate.
The base board (with the processor) can be fitted under the main MS board in the standard MS case with the DB37 under the MS board on the DB9 end. It does require the removal of the MS voltage regulator heat sink screw and having all the other heat sink components with their screw installed so that the screw head is under the board to take up the least amount of space. The I/O Extender board is 100mm wide which is smaller than the 4" (101.4mm) of the MS board so the fit in the lowest slot is somewhat loose but once the DB37 is attached to the case end plate it should be more secure (some hot melt glue or silicone could be used on the end of the board to secure it even more). In that case, the only wires needed between the 2 boards (MS and I/O Extender) would be the 2 CAN wires. And these could be routed outside using the DB37 connections which would mean no internal wiring.
The board can also be fitted in it's own case. It was designed to fit in the Hammond 1455L1201 or 1455N1201 and one of these cases will be needed if using the 2-board setup. And with the 1455N1201, it would be possible to have 3 boards in the same case with either 3 base boards or one 2-board setup and an addition base board to have a very large number of I/Os. This could be a standalone datalogger setup or used to communicate and log with an MS2/Extra or MS3 ECU.
Of course, once the hardware is there with the initial firmware available, the flexibility of the hardware will allow more applications to be developed. The intention is to have some base code (in C) available for those who want to customize the firmware for their own application. I also plan to write a few applications myself depending on requests and how much demand there is.
And here is a picture of the base board with only the SMD components and the DB37:
You can see the headers around the CPU on the left. These are how the second board will be connected to the base board and all the CPU I/Os are routed to them making all the CPU pins available for future expansion. For more details on the board function have a look at the board's web page: http://jbperf.com/io_extender/index.html. It is still missing quite a bit of information but will be upgraded with time.
Jean
