EZ-USB FX3 Technical Reference Manual, Document Number: 001-76074 Rev. *F 134
General Programmable Interface II (GPIF II)
transition condition is (!CE&&!WE) (a write operation). If the left transition condition evaluates to TRUE, then GPIF II
transitions from the IDLE state to the READ state. If the left transition condition evaluates to FALSE, then the right transition
condition is checked. If the right transition condition evaluates to TRUE, then GPIF II transitions from the IDLE state to the
WRITE state. If neither left nor right conditions evaluate to TRUE, then GPIF II remains in IDLE. Note that the first test
resolves the contention if both f0 and f1 are true.
Figure 7-17. Example State Transitions with Actions
7.4.4 GPIF II Designer Tool
An essential part of working with FX3 GPIF II is the GPIF II Designer tool. The GPIF II Designer tool provides a convenient
graphical user interface (GUI) that allows you to define GPIF II state machines in graphical form. The various GPIF II triggers
and actions are available in an easy-to-use manner, allowing simple addition to the states in the diagram. The tool converts
the user graphical design into a C header file that can be integrated with the firmware application code using the firmware API
framework. The tool also generates warnings and error messages during the graphical entry process. You can create your
own GPIF II designs, but the GPIF II Designer tool also provides a set of "canned" designs for popular interfaces.
Documentation of these interfaces, describing the protocol along with timing diagrams, is available when you open an
example project in GPIF II Designer. As part of its initialization, FX3 firmware copies the settings in the .h file into the
appropriate GPIFII registers.
You can also make minor customizations to these designs to suit the target environment. A detailed description of the tool and
its use is provided in the GPIF II Designer User Guide, which is available when you install the tool with the EZ-USB FX3
Software Development Kit.
7.4.5 GPIF II Hardware Resources
7.4.5.1 Comparators
GPIF II includes an address comparator, a data comparator, and a control comparator. You can set the value of the
comparator and a mask that does a bit-by-bit enable. A trigger is available for these comparators that asserts when the
comparator meets the set limit.
IDLE
If (!CE&&!RE)
READ
(Actions: DR_DATA )
WRITE
(Actions: IN_DATA )
* f0 and f1 are logical functions of trigger signals
If (!CE&&!WE)
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