Major update including work on the usb driver, the console, the loggi…

…ng subsystem, button input handling code and updates for the new board layout.

button.c

@@ -0,0 +1,69 @@
+#include "mk20dx128.h"
+#include "usbserial.h"
+#include "button.h"
+
+static uint8_t down;
+static button_callback callback;
+
+__attribute__((interrupt ("IRQ"))) void lptmr_isr(void)
+{
+    if (!down) {
+        down = 1;
+
+        /* Set the lop power timer for active-low to catch the button
+         * release. */
+
+        LPTMR0_CSR &= ~LPTMR_CSR_TEN;
+        LPTMR0_CSR |= LPTMR_CSR_TPP;
+        LPTMR0_CSR |= LPTMR_CSR_TEN;
+    } else {
+        down = 0;
+
+        if (callback) {
+            callback();
+        }
+
+        /* Set the lop power timer for active-low to catch the next
+         * button press. */
+
+        LPTMR0_CSR &= ~LPTMR_CSR_TEN;
+        LPTMR0_CSR &= ~LPTMR_CSR_TPP;
+        LPTMR0_CSR |= LPTMR_CSR_TEN;
+    }
+
+    LPTMR0_CSR |= LPTMR_CSR_TCF;
+}
+
+void button_set_callback(button_callback new_callback)
+{
+    callback = new_callback;
+}
+
+void button_initialize()
+{
+    /* Enable the low power timer and port C modules. */
+
+    SIM_SCGC5 |= SIM_SCGC5_PORTC | SIM_SCGC5_LPTIMER;
+    PORTC_PCR5 = PORT_PCR_MUX(3) | PORT_PCR_PFE | PORT_PCR_PE;
+
+    /* Reset the low power timer module. */
+
+    LPTMR0_CSR = 0;
+
+    /* Configure for single pulse counting, clocked by the 1kHz LPO
+     * clock and set the glitch filter for 16 rising clock edges. */
+
+    LPTMR0_CSR = LPTMR_CSR_TPS(2) | LPTMR_CSR_TMS | LPTMR_CSR_TIE;
+    LPTMR0_CMR = 0;
+    LPTMR0_PSR = LPTMR_PSR_PCS(1) | LPTMR_PSR_PRESCALE(4);
+
+    /* Enable the timer and the corresponding interrupt. */
+
+    LPTMR0_CSR |= LPTMR_CSR_TEN;
+
+    /* Enable the button interrupt and set its priority as low as it
+     * gets. */
+
+    enable_interrupt(39);
+    prioritize_interrupt(39, 15)
+}

button.h

@@ -0,0 +1,9 @@
+#ifndef __BUTTON__
+#define __BUTTON__
+
+typedef void (*button_callback)();
+
+void button_initialize();
+void button_set_callback(button_callback new_callback);
+
+#endif

console

@@ -0,0 +1,85 @@
+#!/bin/bash
+
+history -r .console_history
+quit=false
+
+# Suppress error messages to get rid of kill notifications.
+
+#exec 2>/dev/null
+
+while ! $quit; do
+    device=$(ls -1 /dev | grep ttyACM | head -n 1)
+
+    # Wait for the file to become available, if necessary.
+
+    if [ ! $device ]; then
+        echo "Waiting for device to come on-line..."
+
+        while file=$(inotifywait /dev/ -qe create --format %f); do
+            if [[ $file = ttyACM* ]]; then
+                device=$file
+                break;
+            fi
+        done
+
+        while [ ! -w /dev/$device -o ! -w /dev/$device ]; do
+            sleep 1
+        done
+    fi
+
+    echo "Using device $device."
+
+    # Set up a redirect from stdin to fd 3.
+
+    exec 3<&0
+
+    # Start the console in a subprocess and let it source its input from
+    # fd 3.
+
+    stty 4000000 -icrnl -onlcr -isig -icanon -opost -echo < /dev/$device
+
+    cat /dev/$device &
+    catpid=$!
+    disown $catpid
+
+    (
+        while read -e line; do
+            history -s "$line"
+            echo "$line" > /dev/$device
+        done
+    ) 0<&3 &
+
+    readpid=$!
+
+    trap "kill $readpid" SIGINT
+
+    # Wait for the device to disappear.
+
+    (
+        while file=$(inotifywait /dev/ -qe delete --format %f); do
+            if [ "$file" = "$device" ]; then
+                kill $readpid 2>/dev/null
+                break
+            fi
+        done
+    ) &
+
+    waitpid=$!
+    disown $waitpid
+
+    if wait $readpid 2>/dev/null; then
+        quit=true
+    else
+        echo "Device went off-line."
+    fi
+
+    trap - SIGINT
+    pkill -P $readpid,$catpid,$waitpid 2>/dev/null
+    kill $readpid $catpid $waitpid 2>/dev/null
+
+    # Restore stdin and close fd 3.
+
+    exec 0<&3 3<&-
+done
+
+history -w .console_history