Motorola MCF5282, MCF5281 user manual Port QA Signal Functions, Port QA Analog Input Signals

Models: MCF5282 MCF5281

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Signals

Aborts the conversion sequence in progress

Makes the data direction register (DDRQA), port data registers (PORTQA and PORTQB), control registers (QACR2, QACR1, and QACR0) and the status registers (QASR1 and QASR0) read-only. Only the module configuration register (QADCMCR) remains writable.

Makes the RAM inaccessible, so that valid data cannot be read from RAM (result word table and CCW) or written to RAM (result word table and CCW)

Resets QACR1, QACR2, QASR0, and QASR1

Holds the QADC periodic/interval timer in reset

Because the bias currents to the analog circuit are turned off in stop mode, the QADC requires some recovery time (tSR) to stabilize the analog circuits.

27.4 Signals

The QADC uses the external signals shown in Figure 27-2.There are eight channel/port signals that can support up to 18 channels when external multiplexing is used (including internal channels). All of the channel signals also have some general-purpose input or input/output (GPIO) functionality. In addition, there are also two analog reference signals and two analog submodule power signals.

The QADC has external trigger inputs and multiplexer outputs that are shared with some of the analog input signals.

27.4.1 Port QA Signal Functions

The four port QA signals can be used as analog inputs or as a bidirectional 4-bit digital input/output port.

27.4.1.1Port QA Analog Input Signals

When used as analog inputs, the four port QA signals are referred to as AN[56:55, 53:52].

27-4

MCF5282 User’s Manual

MOTOROLA

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Motorola MCF5282, MCF5281 user manual Port QA Signal Functions, Port QA Analog Input Signals