Description

This section describes how to use macros provided by eCos to manage GPIO functionality on the MPC83XX processors.

The MPC83XX HAL provides a number of macros to support the encoding of GPIO pin identity and configuration into a single 32 bit descriptor. This is useful to drivers and other packages that need to configure and use different lines for different devices.

A descriptor is created with CYGHWR_HAL_MPC83XX_GPIO(ctlr, bit, mode) which takes the following arguments:

The following examples show how this macro may be used:

// Define controller 1 pin 10 as an input
#define CYGHWR_HAL_MPC8309_PIN1               CYGHWR_HAL_MPC83XX_GPIO( 1, 10, INPUT )

// Define controller 2 pin 23 as an open drain output
#define CYGHWR_HAL_MPC8309_PIN23              CYGHWR_HAL_MPC83XX_GPIO( 2, 23, OUTPUT_OPENDRAIN )

Additionally, the macro CYGHWR_HAL_MPC83XX_GPIO_NONE may be used in place of a pin descriptor and has a value that no valid descriptor can take. It may therefore be used as a placeholder where no GPIO pin is present or to be used.

The remaining macros all take a GPIO pin descriptor as an argument. CYGHWR_HAL_MPC83XX_GPIO_SET configures the pin according to the descriptor and must be called before any other macros. CYGHWR_HAL_MPC83XX_GPIO_OUT sets the output to the value of the least significant bit of the val argument. The val argument of CYGHWR_HAL_MPC83XX_GPIO_IN should be a pointer to an int, which will be set to 0 if the pin input is zero, and 1 otherwise.