MISE Hardware Errata

MISE 1.0 PCB

1. The unit will not boot without the WIZ830MJ Ethernet module in place.
   
   Explanation: The Ethernet module drives an active-low interrupt signal to the FPGA, where it is combined with other system interrupts to generate the interrupt signal to the TRS-80 CPU. Without the Ethernet module in place, its interrupt signal is undriven. The FPGA pin used by that signal is not capable of having an internal pull-up, so the TRS-80 may see a constant interrupt, preventing it from booting.



2. The pushbutton on the FPGA module should not be used.
   
   Explanation: The pushbutton (located on the underside of the module) was intended to provide a hardware reset to the MISE. Due to a board layout error its FPGA pin is allocated to an output signal. Pressing the pushbutton will short this signal to ground, potentially damaging the FPGA.

   The reset button in the Model I keyboard unit provides a hardware reset to MISE.

No known issues.

Back to the main page