Model 28 Synchronization Upgrade
	New Firmware: This page announces and describes a non-commercial offering of a new executable for the Plan B Model 28 Tap Clock module.   This new executable programs as firmware into the microcontroller heart of the module. Feature Summary: This new firmware, combined with some form of input clock inversion, substantially increases the modules ability to synchronize with external clock inputs applied to the "phaselock" input.   Additionally, a new output is provided which emits at 24 times the input signal. This new output allows for companion circuitry which could augment the frequency multiplication available from the panel face of the module. Availability: As a non-commercial offering, there is no charge for the executable itself.   As this effort is not factory subsidized, a small cost incurs for the upgrade of an existing module or for provisioning of a new AT89C2051-24 microcontroller for user upgrade. The fee schedule can be referenced here. Contact: North American owners should contact Big City Music for this upgrade, European owners can contact Tim Stinchombe.

Hardware Note: Installation of this new firmware, into a Tap Clock module, does not by itself result in input clock synchronization. Signals routing to an unmodified Tap Clock module's "Phaselock" input, do not synchronize unless they are inverted.   The graphic right explains this requirement. The required inversion can be achieved by inverting the signal prior to connection to the module or by the addition of an inverting circuit to the module itself.   An example of a simple hardware modification for producing the required inversion can be reference here
Additional Information: A document describing Installation, Modification, and Feature Functionality, can be found here. Firmware Operations Manual