Basic support for GPIOs 0-15.

Start new 'core' component for low-level parts

Progress towards #8

core/esp_iomux.c

@@ -0,0 +1,20 @@
+/* Compiler-level implementation for esp/iomux.h and esp/iomux_private.h
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2015 Superhouse Automation Pty Ltd
+ * BSD Licensed as described in the file LICENSE
+ */
+#include "esp/iomux.h"
+#include "common_macros.h"
+
+/* These are non-static versions of the GPIO mapping tables in
+   iomux.h, so if they need to be linked only one copy is linked for
+   the entire program.
+
+   These are only ever linked in if the arguments to gpio_to_ionum
+   or ionum_to_gpio are not known at compile time.
+
+   Arrays are declared as 32-bit integers in IROM to save RAM.
+*/
+const IROM uint32_t GPIO_TO_IOMUX_MAP[] = _GPIO_TO_IOMUX;
+const IROM uint32_t IOMUX_TO_GPIO_MAP[] = _IOMUX_TO_GPIO;