Low-level Access to Peripherals

In some cases, a non-standard use of the peripheral could be required and it might be more efficient to write a custom peripheral driver from scratch than to use the bean. In addition, there are special features present only on a particular chip derivative (not supported by the bean) that could make the user routines more effective; however, the portability of such code is reduced.

Peripheral Initialization

It is possible to use Processor Expert to generate only the initialization code (function) for a peripheral using a Peripheral initialization beans. The user can choose a suitable Peripheral initialization bean for the given peripheral using a Bean Selector under a Peripherals tab. See chapter Bean Selector for details. The initial values which will be set to the peripheral control registers could be viewed by the Peripheral Initialization window. See chapter Peripheral Initialization for details.

Peripheral Driver Implementation

• Processor Expert System Library (PESL)
• Direct control of the CPU registers

Warning: Incorrect use of PESL or change in registers of the peripheral, which is controlled by any Bean driver can cause the incorrect Bean driver function.

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