Implement BatDis driver

BatDis.c

+///\file
+///\brief   Driver for the battery disable in-/output on the ProgBob board
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <util/delay.h>
+
+#include "BatDis.h"
+#include "LEDs.h"
+
+
+///\brief   Prescaler for BATDIS sampling
+static uint32_t counter = 1;
+
+///\brief   BATDIS sampling disable state
+static bool sampling_disabled = false;
+
+
+///\brief   Samples BATDIS
+///\details Configures BATDIS as input, waits a few microseconds, reads the pin's logic level and
+///         sets it back to output mode.
+///\returns the BATDIS logical level
+static inline bool sample_batdis(void)
+{
+    BATDIS_DDR &= ~BATDIS_MASK;
+    _delay_us(20);
+    bool level = (BATDIS_PIN & BATDIS_MASK) / BATDIS_MASK;
+    BATDIS_DDR |= BATDIS_MASK;
+    return level;
+}
+
+
+void batdis_disable_sampling(const bool disable)
+{
+    sampling_disabled = disable;
+    if (!sampling_disabled) {
+        counter = 1;
+    }
+}
+
+void batdis_init(void)
+{
+    BATDIS_DDR  |= BATDIS_MASK;
+    BATDIS_PORT |= BATDIS_MASK;
+}
+
+void batdis_task(void)
+{
+    if (sampling_disabled) {
+        return;
+    }
+
+    --counter;
+    if (counter > 0) {
+        return;
+    }
+    counter = BATDIS_SCAN_INTERVAL;
+
+    bool connected = !sample_batdis();
+    uint32_t color = connected ? LEDS_COLOR_BOB3_CONNECTED : LEDS_COLOR_BOB3_NOT_CONNECTED;
+    leds_set_color(LEDS_LED_RIGHT, color);
+}

BatDis.h

+///\file
+///\brief   Driver for the battery disable in-/output on the ProgBob board
+
+#ifndef BATDIS_H
+#define BATDIS_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <avr/io.h>
+
+
+///\brief   Bitmask for BATDIS pin
+#define BATDIS_MASK             (1 << 7)
+
+///\brief   DDR register for BATDIS in-/output
+#define BATDIS_DDR              DDRC
+
+///\brief   PORT register for BATDIS in-/output
+#define BATDIS_PIN              PINC
+
+///\brief   PORT register for BATDIS in-/output
+#define BATDIS_PORT             PORTC
+
+///\brief   BATDIS sample interval in [number of invocations]
+///\see     batdis_task
+#define BATDIS_SCAN_INTERVAL    60000
+
+
+///\brief   En-/disables periodic sampling of BATDIS
+///\param   disable
+///             if `true` sampling is disabled
+///\see     batdis_task
+void batdis_disable_sampling(bool disable);
+
+///\brief   Initializes the BATDIS driver
+///\details Configures the BATDIS GPIO as output and sets it high
+void batdis_init(void);
+
+///\brief   Periodically samples BATDIS and indicates if a BOB3 board is connected
+///\details Temporarily configures the BATDIS GPIO as input and reads its logic state. If the GPIO
+///         is pulled low, the right LED's color is set to indicate that a BOB3 board is connected.
+///\see     BATDIS_SCAN_INTERVAL
+///\see     batdis_sampling_enabled
+void batdis_task(void);
+
+
+#endif

Makefile

@@ -18,7 +18,7 @@ F_CPU        = 16000000
 F_USB        = $(F_CPU)
 OPTIMIZATION = s
 TARGET       = ProgBob
-SRC          = $(TARGET).c LEDs.c AVRISPDescriptors.c \
+SRC          = $(TARGET).c BatDis.c LEDs.c AVRISPDescriptors.c \
                Lib/V2Protocol.c Lib/V2ProtocolParams.c \
                Lib/ISP/ISPProtocol.c Lib/ISP/ISPTarget.c\
                Lib/XPROG/XPROGProtocol.c Lib/XPROG/XPROGTarget.c Lib/XPROG/XMEGANVM.c Lib/XPROG/TINYNVM.c \

ProgBob.c

@@ -45,6 +45,7 @@
 #include "Lib/V2Protocol.h"
 #include "AVRISPDescriptors.h"
 
+#include "BatDis.h"
 #include "LEDs.h"
 
 
@@ -66,6 +67,7 @@ static void avrisp_task(void)
     if (Endpoint_IsOUTReceived())
     {
         if (timeout == 0) {
+            batdis_disable_sampling(true);
             leds_disable_fading(true);
             leds_set_color(LEDS_LED_RIGHT, LEDS_COLOR_BOB3_PROGRAMMING);
         }
@@ -81,6 +83,7 @@ static void avrisp_task(void)
         }
         --timeout;
         if (timeout == 0) {
+            batdis_disable_sampling(false);
             leds_disable_fading(false);
         }
     }
@@ -98,6 +101,7 @@ int main(void)
     clock_prescale_set(clock_div_1);
 
     // Hardware initialization
+    batdis_init();
     leds_init();
     leds_set_color(LEDS_LED_LEFT,  LEDS_COLOR_USB_NOT_READY);
     leds_set_color(LEDS_LED_RIGHT, LEDS_COLOR_BOB3_NOT_CONNECTED);
@@ -111,6 +115,7 @@ int main(void)
     {
         USB_USBTask();
         avrisp_task();
+        batdis_task();
     }
     return 0;
 }