Initial firmware commit.

firmware/common/portapack_io.cpp

@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * 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 2, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "portapack_io.hpp"
+
+#include "lpc43xx_cpp.hpp"
+using namespace lpc43xx;
+
+#include "utility.hpp"
+
+#include <ch.h>
+
+#include <cstdint>
+
+namespace portapack {
+
+void IO::init() {
+	data_mask_set();
+	data_write_high(0);
+
+	dir_read();
+	lcd_rd_deassert();
+	lcd_wr_deassert();
+	io_stb_deassert();
+	addr(0);
+
+	gpio_dir.output();
+	gpio_lcd_rd.output();
+	gpio_lcd_wr.output();
+	gpio_io_stbx.output();
+	gpio_addr.output();
+	gpio_rot_a.input();
+	gpio_rot_b.input();
+}
+
+void IO::lcd_backlight(const bool value) {
+	io_reg = (io_reg & 0x7f) | ((value ? 1 : 0) << 7);
+	io_write(1, io_reg);
+}
+
+void IO::lcd_reset_state(const bool active) {
+	/* NOTE: This overwrites the contents of the IO register, which for now
+	 * have no significance. But someday...?
+	 */
+	io_reg = (io_reg & 0xfe) | ((active ? 1 : 0) << 0);
+	io_write(1, io_reg);
+}
+
+uint32_t IO::io_update(const TouchPinsConfig write_value) {
+	/* Very touchy code to save context of PortaPack data bus while the
+	 * resistive touch pin drive is changed. Order of operations is
+	 * important to prevent latching spurious data into the LCD or IO
+	 * registers.
+	 */
+
+	const auto save_data = data_read();
+	const auto addr = gpio_addr.read();
+	const auto dir = gpio_dir.read();
+
+	io_stb_assert();
+
+	/* Switch to read */
+	dir_read();
+	addr_0();
+	__asm__("nop");
+	__asm__("nop");
+	__asm__("nop");
+	const auto switches_raw = data_read();
+
+	/* Switch to write */
+	data_write_low(toUType(write_value));
+	dir_write();
+	__asm__("nop");
+	__asm__("nop");
+	__asm__("nop");
+	io_stb_deassert();
+
+	data_write_low(save_data);
+	if( dir ) {	/* 0 (write) -> 1 (read) */
+		dir_read();
+	}
+	gpio_addr.write(addr);
+
+	return switches_raw;
+}
+
+}