efm32: energy management unit headers and example

examples/efm32/tinygecko/efm32-tg-stk3300/lightswitch/lightswitch-interrupt.c

@@ -0,0 +1,71 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 chrysn <chrysn@fsfe.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/efm32/tinygecko/irq.h>
+#include <libopencm3/efm32/tinygecko/emu.h>
+
+#define ISER0 MMIO32(0xE000E100)
+
+void interrupt_setup()
+{
+	// These are the ports the pin interrupts for 8 and 11 are to be
+	// configured to, and they should trigger on falling edge.
+	
+	GPIO_EXTIPSELH = (BUTTON0_PORT_EXTIPSEL << ((BUTTON0_PIN_NUMBER-8)*4)) |
+	                 (BUTTON1_PORT_EXTIPSEL << ((BUTTON1_PIN_NUMBER-8)*4));
+
+	GPIO_EXTIFALL = BUTTON0_PIN | BUTTON1_PIN;
+
+	// Enable interrupts on the GPIO side
+	
+	GPIO_INSENSE = GPIO_INSENSE_INT;
+	GPIO_IEN = BUTTON0_PIN | BUTTON1_PIN;
+
+	// Enable GPIO interrupts in NVIC
+
+	ISER0 = (1<<IRQ_GPIO_EVEN) | (1<<IRQ_GPIO_ODD);
+}
+
+int main(void)
+{
+	gpio_setup();
+	interrupt_setup();
+
+	while(1) {
+		emu_sleep_em1();
+	};
+}
+
+void gpio_even_isr()
+{
+	// Clearing the GPIO interrupt pending register. While the NVIC
+	// interrupt pending register gets cleared automatically once it jumps
+	// here, the pin's pending state has to be cleared explicitly.
+	// (Dispatch to different subroutines for different even pins that
+	// trigger an interrupt would happen here.)
+	GPIO_IFC = BUTTON0_PIN;
+	led_on();
+}
+
+void gpio_odd_isr()
+{
+	// See gpio_even_isr.
+	GPIO_IFC = BUTTON1_PIN;
+	led_off();
+}