1 files changed, 193 insertions, 0 deletions
diff --git a/boards/ek-lm4f120xl/drivers/buttons.c b/boards/ek-lm4f120xl/drivers/buttons.c
new file mode 100644
index 0000000..4415168
--- /dev/null
+++ b/boards/ek-lm4f120xl/drivers/buttons.c
@@ -0,0 +1,193 @@
+//*****************************************************************************
+//
+// buttons.c - Evaluation board driver for push buttons.
+//
+// Copyright (c) 2012 Texas Instruments Incorporated.  All rights reserved.
+// Software License Agreement
+// 
+// Texas Instruments (TI) is supplying this software for use solely and
+// exclusively on TI's microcontroller products. The software is owned by
+// TI and/or its suppliers, and is protected under applicable copyright
+// laws. You may not combine this software with "viral" open-source
+// software in order to form a larger program.
+// 
+// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
+// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
+// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
+// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
+// DAMAGES, FOR ANY REASON WHATSOEVER.
+// 
+// This is part of revision 9453 of the EK-LM4F120XL Firmware Package.
+//
+//*****************************************************************************
+
+#include "inc/hw_types.h"
+#include "inc/hw_memmap.h"
+#include "inc/hw_gpio.h"
+#include "driverlib/sysctl.h"
+#include "driverlib/rom.h"
+#include "driverlib/pin_map.h"
+#include "driverlib/gpio.h"
+#include "drivers/buttons.h"
+
+//*****************************************************************************
+//
+//! \addtogroup buttons_api
+//! @{
+//
+//*****************************************************************************
+
+//*****************************************************************************
+//
+// Holds the current, debounced state of each button.  A 0 in a bit indicates
+// that that button is currently pressed, otherwise it is released.
+// We assume that we start with all the buttons released (though if one is
+// pressed when the application starts, this will be detected).
+//
+//*****************************************************************************
+static unsigned char g_ucButtonStates = ALL_BUTTONS;
+
+//*****************************************************************************
+//
+//! Polls the current state of the buttons and determines which have changed.
+//!
+//! \param pucDelta points to a character that will be written to indicate
+//! which button states changed since the last time this function was called.
+//! This value is derived from the debounced state of the buttons.
+//! \param pucRawState points to a location where the raw button state will
+//! be stored.
+//!
+//! This function should be called periodically by the application to poll the
+//! pushbuttons.  It determines both the current debounced state of the buttons
+//! and also which buttons have changed state since the last time the function
+//! was called.
+//!
+//! In order for button debouncing to work properly, this function should be
+//! caled at a regular interval, even if the state of the buttons is not needed
+//! that often.
+//!
+//! If button debouncing is not required, the the caller can pass a pointer
+//! for the \e pucRawState parameter in order to get the raw state of the
+//! buttons.  The value returned in \e pucRawState will be a bit mask where
+//! a 1 indicates the buttons is pressed.
+//!
+//! \return Returns the current debounced state of the buttons where a 1 in the
+//! button ID's position indicates that the button is pressed and a 0
+//! indicates that it is released.
+//
+//*****************************************************************************
+unsigned char
+ButtonsPoll(unsigned char *pucDelta, unsigned char *pucRawState)
+{
+    unsigned long ulDelta;
+    unsigned long ulData;
+    static unsigned char ucSwitchClockA = 0;
+    static unsigned char ucSwitchClockB = 0;
+
+    //
+    // Read the raw state of the push buttons.  Save the raw state
+    // (inverting the bit sense) if the caller supplied storage for the
+    // raw value.
+    //
+    ulData = (ROM_GPIOPinRead(BUTTONS_GPIO_BASE, ALL_BUTTONS));
+    if(pucRawState)
+    {
+        *pucRawState = (unsigned char)~ulData;
+    }
+
+    //
+    // Determine the switches that are at a different state than the debounced
+    // state.
+    //
+    ulDelta = ulData ^ g_ucButtonStates;
+
+    //
+    // Increment the clocks by one.
+    //
+    ucSwitchClockA ^= ucSwitchClockB;
+    ucSwitchClockB = ~ucSwitchClockB;
+
+    //
+    // Reset the clocks corresponding to switches that have not changed state.
+    //
+    ucSwitchClockA &= ulDelta;
+    ucSwitchClockB &= ulDelta;
+
+    //
+    // Get the new debounced switch state.
+    //
+    g_ucButtonStates &= ucSwitchClockA | ucSwitchClockB;
+    g_ucButtonStates |= (~(ucSwitchClockA | ucSwitchClockB)) & ulData;
+
+    //
+    // Determine the switches that just changed debounced state.
+    //
+    ulDelta ^= (ucSwitchClockA | ucSwitchClockB);
+
+    //
+    // Store the bit mask for the buttons that have changed for return to
+    // caller.
+    //
+    if(pucDelta)
+    {
+        *pucDelta = (unsigned char)ulDelta;
+    }
+
+    //
+    // Return the debounced buttons states to the caller.  Invert the bit
+    // sense so that a '1' indicates the button is pressed, which is a
+    // sensible way to interpret the return value.
+    //
+    return(~g_ucButtonStates);
+}
+
+//*****************************************************************************
+//
+//! Initializes the GPIO pins used by the board pushbuttons.
+//!
+//! This function must be called during application initialization to
+//! configure the GPIO pins to which the pushbuttons are attached.  It enables
+//! the port used by the buttons and configures each button GPIO as an input
+//! with a weak pull-up.
+//!
+//! \return None.
+//
+//*****************************************************************************
+void
+ButtonsInit(void)
+{
+    //
+    // Enable the GPIO port to which the pushbuttons are connected.
+    //
+    ROM_SysCtlPeripheralEnable(BUTTONS_GPIO_PERIPH);
+
+    //
+    // Unlock PF0 so we can change it to a GPIO input
+    // Once we have enabled (unlocked) the commit register then re-lock it
+    // to prevent further changes.  PF0 is muxed with NMI thus a special case.
+    //
+    HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY_DD;
+    HWREG(BUTTONS_GPIO_BASE + GPIO_O_CR) |= 0x01;
+    HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = 0;
+
+    //
+    // Set each of the button GPIO pins as an input with a pull-up.
+    //
+    ROM_GPIODirModeSet(BUTTONS_GPIO_BASE, ALL_BUTTONS, GPIO_DIR_MODE_IN);
+    ROM_GPIOPadConfigSet(BUTTONS_GPIO_BASE, ALL_BUTTONS,
+                         GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD_WPU);
+
+    //
+    // Initialize the debounced button state with the current state read from
+    // the GPIO bank.
+    //
+    g_ucButtonStates = ROM_GPIOPinRead(BUTTONS_GPIO_BASE, ALL_BUTTONS);
+}
+
+//*****************************************************************************
+//
+// Close the Doxygen group.
+//! @}
+//
+//*****************************************************************************