|
The
68000 CPU-2.1 Board |
| Jumpers |
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Default settings: |
place Jumpers as
shown in RED below |
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J1 NMI - Non
Maskable Interrupt |
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This Jumper
enables/disables NMI interrupts from the on board pushbutton
S2 and CN3 the external NMI pushbutton connector. |
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J1 open - disabled |
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J1 short - enabled |
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J2 DTACK |
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This Jumper allows
DTACK to be grounded for test purposes. |
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J2 pins 1-2 short
- DTACK grounded |
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J2 pins 2-3 short
- normal operation |
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J3 BERR |
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This Jumper
enables/disables the Bus Error feature. |
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J3 open - disabled |
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J3 short - enabled |
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J4 Data Bus
Bias |
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This Jumper
controls the bias applied to the 68000 data bus. |
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J4 pins 1-2 short
- 68000 data bus biased low |
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J4 pins 2-3 short
- 68000 data bus biased high |
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| CN2 RESET |
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This Connector
serves two purposes: |
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| 1. Connector
for normally open pushbutton switch (External RESET). |
| 2. Allows
RESET & HALT to be grounded for test purposes (use
shorting Jumper). |
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| CN2 short
- RESET & HALT grounded |
| CN2 open
- normal operation |
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When RESET & HALT
are grounded the 68000 address and data lines are
disconnected i.e. they are in
a high impedance state allowing external manipulation of
the address and data lines. |
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| CN3 NMI |
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| Connector for
normally open pushbutton switch (External NMI). |
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