SC513, v1.0, User Guide

The backplane has 6 vertical sockets for Z50Bus compatible cards. It also has one horizontal socket to allow a modular backplane extension section to be connected. Alternatively, a horizontally mounted Z50Bus compatible card can be connected.

Power is supplied to the backplane from either the barrel socket or the screw terminals. This needs to be 5-volts (4.75 to 5.25 volts) at typically a few hundred milliamperes.

The backplane includes a voltage supervisor and reset device (U1). This device will hold the system in reset if the supply voltage is below approximately 4.75 volts. If the system does not start, always check the reset signal is not being held low and also that the supply voltage reaching the backplane is at least 4.75 volts.

The only complication using this backplane is the Z80 mode 2 interrupt daisy chain signals, IEI and IEO.

The interrupt daisy chain consists of a signal that connects the output of one card (IEO) to the input of the next (IEI). The position of a card in the chain (ie. its position on the backplane) determines its interrupt priority. If you are using this feature you must not leave a gap between cards that support interrupts, as this will break the chain.

If you are using mode 2 interrupts and you have either a backplane section or a Z50Bus card fitted to the horizontal bus socket (SK7) then you need to fit a jumper shunt to JP1. This jumper has one position for a backplane section and another for a Z50Bus card.

One thing worth noting is that the ON/OFF switch only turns the system on and off if it is powered from the 5-volt input connectors on the backplane. If power is introduced from a Z50Bus card, such as a serial port, the switch will only isolate power from the power connectors on the backplane. not from the cards connected to the backplane.

The backplane is a modular design allowing it to be extended using the LiNC 5-slot backplane section.

Alternatively, the horizontal socket can be used to connect a Z50Bus card. This can be very useful when debugging hardware.

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