portapack-mayhem/firmware/common/portapack_io.cpp
2017-07-18 13:17:10 -07:00

111 lines
2.6 KiB
C++

/*
* 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) {
io_reg = (io_reg & 0xfe) | ((active ? 1 : 0) << 0);
io_write(1, io_reg);
}
void IO::audio_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 & 0xfd) | ((active ? 1 : 0) << 1);
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;
}
}