ChibiOS 2.6.8, until I can figure out where to get it from git.

firmware/chibios/testhal/STM32F4xx/GPT/main.c

@@ -0,0 +1,96 @@
+/*
+    ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#include "ch.h"
+#include "hal.h"
+
+/*
+ * GPT2 callback.
+ */
+static void gpt2cb(GPTDriver *gptp) {
+
+  (void)gptp;
+  palSetPad(GPIOD, GPIOD_LED5);
+  chSysLockFromIsr();
+  gptStartOneShotI(&GPTD3, 1000);   /* 0.1 second pulse.*/
+  chSysUnlockFromIsr();
+}
+
+/*
+ * GPT3 callback.
+ */
+static void gpt3cb(GPTDriver *gptp) {
+
+  (void)gptp;
+  palClearPad(GPIOD, GPIOD_LED5);
+}
+
+/*
+ * GPT2 configuration.
+ */
+static const GPTConfig gpt2cfg = {
+  10000,    /* 10kHz timer clock.*/
+  gpt2cb,   /* Timer callback.*/
+  0
+};
+
+/*
+ * GPT3 configuration.
+ */
+static const GPTConfig gpt3cfg = {
+  10000,    /* 10kHz timer clock.*/
+  gpt3cb,   /* Timer callback.*/
+  0
+};
+
+/*
+ * Application entry point.
+ */
+int main(void) {
+
+  /*
+   * System initializations.
+   * - HAL initialization, this also initializes the configured device drivers
+   *   and performs the board-specific initializations.
+   * - Kernel initialization, the main() function becomes a thread and the
+   *   RTOS is active.
+   */
+  halInit();
+  chSysInit();
+
+  /*
+   * Initializes the GPT drivers 2 and 3.
+   */
+  gptStart(&GPTD2, &gpt2cfg);
+  gptPolledDelay(&GPTD2, 10); /* Small delay.*/
+  gptStart(&GPTD3, &gpt3cfg);
+  gptPolledDelay(&GPTD3, 10); /* Small delay.*/
+
+  /*
+   * Normal main() thread activity, it changes the GPT1 period every
+   * five seconds.
+   */
+  while (TRUE) {
+    palSetPad(GPIOD, GPIOD_LED4);
+    gptStartContinuous(&GPTD2, 5000);
+    chThdSleepMilliseconds(5000);
+    gptStopTimer(&GPTD2);
+    palClearPad(GPIOD, GPIOD_LED4);
+    gptStartContinuous(&GPTD2, 2500);
+    chThdSleepMilliseconds(5000);
+    gptStopTimer(&GPTD2);
+  }
+}