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Reference for unit 'fpgpio' (#pascalio)

TGpioRegisterController

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

Generic class for I/O controller using registers

Declaration

Source position: fpgpio.pas.bak line 172

`type TGpioRegisterController = class(TGpioController)`
`protected`
`function GetActiveLow(); override;`
`function GetDirection(); override;`
`function GetValue(); override;`
`procedure SetActiveLow(); override;`
`procedure SetDirection(); override;`
`procedure SetValue(); override;`
`function GetRegister(); virtual; abstract;`		Address of a requested register
`function GetRegisterValue(); virtual; abstract;`		Retrieves the value of a given register
`procedure SetRegisterValue(); virtual; abstract;`		Set the value of a given register
`function GetRegisterValueS(); virtual;`		Convenience method for getting a value for a specific pin
`procedure SetRegisterValueS(); virtual;`		Convenience method for setting a value for a specific pin
`property RegisterValue []: TRegisterValue; [rw]`		Value of a given register
`end;`

Inheritance

`TGpioRegisterController`		Generic class for I/O controller using registers
\|
`TGpioController`		Generic class for a goup of GPIO pins controlled together
\|
`TObject`

Description

Many external I/O expanders provide an interface which exposes the internal registers to the contoller. This base class provides an basic interface to these I/O expanders.

Setting and getting values basically operate on 3 methods:

function GetRegister(): Getting the adress of the register and the position of the pin within this register.
function GetRegisterValue(): Reading the current TRegisterValue.
procedure SetRegisterValue(): Setting the new value if desired.
If you are interested in only one bit of a register, you may use the convenience methods TGpioRegisterController.GetRegisterValueS and TGpioRegisterController.SetRegisterValueS.

Only expanders with 8 bit registers are supported. This does not mean, the expander may have at maximum 8 GPIO channels. An expander may provide more than one register for one task.