From e018ceebed74b8223482bc9d1ed0b31c938381da Mon Sep 17 00:00:00 2001
From: Yuval Adam <yuv.adm@gmail.com>
Date: Mon, 29 Oct 2012 23:04:19 +0200
Subject: New example files

---
 .../ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c  | 140 +++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 boards/ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c

(limited to 'boards/ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c')

diff --git a/boards/ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c b/boards/ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c
new file mode 100644
index 0000000..5ad0720
--- /dev/null
+++ b/boards/ek-lm4f120xl-boost-capsense/drivers/CTS_HAL.c
@@ -0,0 +1,140 @@
+//*****************************************************************************
+//
+// CTS_HAL.c - Capacative Sense Library Hardware Abstraction Layer. 
+//
+// 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_gpio.h"
+#include "inc/hw_memmap.h"
+#include "inc/hw_nvic.h"
+#include "drivers/CTS_structure.h"
+#include "drivers/CTS_HAL.h"
+
+//*****************************************************************************
+//
+// Function to get a capacitance reading from a single-pin RC-based capacitive
+// sensor. This function assumes that the capacitive sensor is charged by a
+// GPIO, and then discharged through a resistor to GND. The same GPIO used to
+// perform the charging will be used as an input during discharge to sense when
+// the capacitor's voltage has decreased to at least VIL. The function will
+// execute several cycles of this, and report how long the process took in
+// units of SysTick counts. This count should be proportional to the current
+// capacitance of the sensor, and the resistance of the discharge resistor.
+//
+//*****************************************************************************
+void
+CapSenseSystickRC(const tSensor *group, unsigned long *counts)
+{
+    unsigned char ucIndex;
+
+    //
+    // Run an RC based capacitance measurement routine on each element in the
+    // sensor array.
+    //
+    for(ucIndex = 0; ucIndex < (group->ucNumElements); ucIndex++)
+    {
+        //
+        // Reset Systick to zero (probably not necessary for most cases, but we
+        // want to make sure that Systick doesn't roll over.)
+        //
+        HWREG(NVIC_ST_CURRENT) = 0x0;
+
+        //
+        // Grab a count number from the capacitive sensor element.
+        //
+        counts[ucIndex] = 
+            CapSenseElementSystickRC(group->Element[ucIndex]->ulGPIOPort,
+                                     group->Element[ucIndex]->ulGPIOPin,
+                                     group->ulNumSamples);
+                                             
+    }
+}
+
+//*****************************************************************************
+//
+//
+//
+//
+//*****************************************************************************
+unsigned long
+CapSenseElementSystickRC(unsigned long ulGPIOPort, unsigned long ulGPIOPin,
+                         unsigned long ulNumSamples)
+{
+    volatile unsigned long ulStartTime;
+    volatile unsigned long ulEndTime;
+    unsigned long ulIndex;
+    unsigned long ulGPIODataReg;
+    unsigned long ulGPIODirReg;
+
+    //
+    // Save off our GPIO information.
+    //
+    ulGPIODataReg = (ulGPIOPort + (GPIO_O_DATA + (ulGPIOPin << 2)));
+    ulGPIODirReg = ulGPIOPort + GPIO_O_DIR;
+
+    //
+    // Grab the time
+    //
+    ulStartTime = HWREG(NVIC_ST_CURRENT);
+    
+    //
+    // Loop until we have the requisite number of samples.
+    //
+    for(ulIndex = 0; ulIndex < ulNumSamples; ulIndex++)
+    {
+        //
+        // Drive up.
+        //
+        //GPIOPinWrite(ulGPIOPort, ulGPIOPin, ulGPIOPin);
+        HWREG(ulGPIODataReg) = 0xFF;
+
+        //
+        // Configure as input
+        //
+        //GPIOPinTypeGPIOInput(ulGPIOPort, ulGPIOPin);
+        HWREG(ulGPIODirReg) = (HWREG(ulGPIODirReg) & ~(ulGPIOPin));
+
+        //
+        // Wait until the capacitor drains away to ground
+        //
+        //while(GPIOPinRead(ulGPIOPort, ulGPIOPin))
+        while(HWREG(ulGPIODataReg))
+        {
+        }
+
+        //
+        // Configure as an output.
+        //
+        //GPIOPinTypeGPIOOutput(ulGPIOPort, ulGPIOPin);
+        HWREG(ulGPIODirReg) = (HWREG(ulGPIODirReg) | ulGPIOPin);
+    }
+    
+    //
+    // Grab the time, and calculate the difference
+    //
+    ulEndTime = HWREG(NVIC_ST_CURRENT);
+
+    //
+    // Return the time difference
+    //
+    return(ulStartTime - ulEndTime);
+}
-- 
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