Jameco Electronics 3000 ユーザーズマニュアル
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Rabbit 3000 Microprocessor
The functionality of the Parallel Port F pins is not affected for pulse width modulation out-
puts and serial clock outputs, except that the Parallel Port F function and direction regis-
ters should be set up before a conflicting function on Parallel Port A is in use, since
writing to these registers also writes to the Parallel Port A output register.
puts and serial clock outputs, except that the Parallel Port F function and direction regis-
ters should be set up before a conflicting function on Parallel Port A is in use, since
writing to these registers also writes to the Parallel Port A output register.
9.6.1.1 Summary
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If you enable the auxiliary I/O bus, which uses Parallel Port A, then the bug does not
manifest itself and you can use the full functionality of Parallel Port F.
manifest itself and you can use the full functionality of Parallel Port F.
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If you use Parallel Port A as inputs, then the bug does not manifest itself and the full
functionality of Parallel Port F is available.
functionality of Parallel Port F is available.
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If you use Parallel Port A as outputs, then you cannot use Parallel Port F pins as outputs
too, except that you can use the PWM and clock outputs provided that you are aware
that writing to the control registers of Parallel Port F will also write to the data output
register of Parallel Port A. A simple way to resolve this is to leave Parallel Port A as an
input until you complete the setup of Parallel Port F and then switch Parallel Port A to
be an output. You can always use pins on Parallel Port F as inputs.
too, except that you can use the PWM and clock outputs provided that you are aware
that writing to the control registers of Parallel Port F will also write to the data output
register of Parallel Port A. A simple way to resolve this is to leave Parallel Port A as an
input until you complete the setup of Parallel Port F and then switch Parallel Port A to
be an output. You can always use pins on Parallel Port F as inputs.
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If you enable the slave port, then you cannot use Parallel Port F as parallel outputs, but
you can still use the other output functions of Parallel Port F following the precautions
regarding setup described above.
you can still use the other output functions of Parallel Port F following the precautions
regarding setup described above.
The easiest approach to avoid any problem when there is a conflict is to assign inputs and
outputs in such a manner as to avoid the bug. Either Parallel Port A can be used as inputs,
in which case Parallel Port F has full function, or if Parallel Port A cannot be used as
inputs, use any pins on Parallel Port F not used for PWM or serial clock outputs as inputs
and take the precaution of setting up Parallel Port F before the conflicting functionality of
Parallel Port A is enabled.
outputs in such a manner as to avoid the bug. Either Parallel Port A can be used as inputs,
in which case Parallel Port F has full function, or if Parallel Port A cannot be used as
inputs, use any pins on Parallel Port F not used for PWM or serial clock outputs as inputs
and take the precaution of setting up Parallel Port F before the conflicting functionality of
Parallel Port A is enabled.
Parallel Port A
Parallel Port F
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Parallel Inputs
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Full Functionality
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Parallel Outputs
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Parallel Inputs, PWM, Serial Port Clocks
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Slave Port
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Parallel Inputs, PWM, Serial Port Clocks
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Auxiliary I/O Bus
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Full Functionality