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P5040/P5020 Reference Design Board User Guide, Rev. 0
Freescale Semiconductor
45
Configuration
3. Rarely or never altered.
Options 1 and 2 are implemented with DIP-switches and/or options in which it is possible to set software.
Option 3 is normally implemented by resistors that are added/removed by competent technicians.
6.2
Configuration Modes
There are different types of reference board configurations. A list of these configuration types and their
implementation is shown below.
When used with a P5040/P5020, the reference board switches and their default settings are shown in
Appendix A, “Reference board Switch Assignments and Defaults When Used with P5040/P5020
names exactly match the name on the schematics and on the printed-circuit board in most cases, except
where a spare has been newly assigned and only the FPGA has changed.
6.2.1
Configuration Switches
For those signals configured using switches, the configuration logic is as shown in this figure.
Figure 21. Configuration Switch Logic and P5040/P5020
The default action is for the FPGA to transfer the switch setting to the processor configuration pin during
the PORESET_B assertion interval. However, local bus also provides a way to configure certain features
dynamically.
Table 23. Configuration Types
Configuration Type
Implementation
Requires software configuration to
support evaluation
Implemented with “DIP switches” and/or software-settable options
Expected to be easily or often
changed by the end-user or
developer
P5040/P5020
CONFIG_PIN
FPGA
ENx.y
SWx.y
where needed
OVDD
CFGDRV
SW1
EN1
SW2
EN2
...
EEPROM