Freescale Semiconductor Microcontrollers - Manual (Page 619)

ColdFire V1 Full Chip Simulation Connection
FCS Visualization Utilities
619 Microcontrollers Debugger Manual
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Programmable IO_Ports Component
The Programmable IO_Ports window shown in Figure 28.47 consists of five IO_Ports
with eight configurable bits in input or output. In the default configuration all couplers are
in input. The graphical interface suggests the state of each one.
Figure 28.47 Programmable IO_Ports Window
The debugger uses circuits called «input / output couplers » to complete the data exchange
between the processor and peripherals. The peripherals are connected to the data bus in
parallel. The appropriate output circuit catches information on the data bus and saves it (in
a latch) until the next data reception.
The processor perceives the input/output couplers as memory cases with a wired fixed
address. The capability exists to do input/output actions at a known address. In C, access is
accomplished using forced pointers to these addresses.
A read operation when the coupler is in input mode activates this input during all the read
steps. A write operation when the coupler is in output mode activates the output latch
during all write steps.
The programmable IO_Ports allows you to define the coupler in input and output. You
can modify this configuration during program execution. The first step in the test program
is to configure the appropriate couplers.