A Digital Distributorless Ignition System

"A Digital Distributorless Ignition System" appeared as a two-part article in Performance Engineering magazine which is no longer in print, unfortunately.

Part 1 introduces the concept of distributorless ignition systems and also addresses the primary computational core, a Motorola 68HC11 microcontroller and its supporting circuitry.

Part 2 explains the input signal conditioning circuitry and the output coil driver circuit. A blow-by-blow description of the embedded code is also included.

In addition to the articles, here are some supplemental files:

• PC-based ignition system controlling software. (86KB ZIP file)
• Ignition controller schematic. (Postscript file)
• Ignitor and signal conditioning schematic. (Postscript file)
• PAL address decoding file. This is a PALASM (.PDS) file but is text readable. Note that outputs are active low even though the equations don't denote that (PALASM is confusing sometimes).