Add ADB protocol files from blargg's work

- <http://geekhack.org/index.php?topic=14290.msg1070604#msg1070604>

1 files changed, 216 insertions, 0 deletions

diff --git a/converter/adb_usb/adb_blargg.c b/converter/adb_usb/adb_blargg.c
new file mode 100644
index 0000000000..963758c533
--- /dev/null
+++ b/converter/adb_usb/adb_blargg.c
@@ -0,0 +1,216 @@
+// Bit-banged implementation without any use of interrupts.
+// Data pin must have external 1K pull-up resistor.
+// Operates data pin as open-collector output.
+
+#include "adb_blargg.h"
+
+#ifdef HAVE_CONFIG_H
+	#include "config.h"
+#endif
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+
+// Copyright 2011 Jun WAKO <wakojun@gmail.com>
+// Copyright 2013 Shay Green <gblargg@gmail.com>
+// See bottom of file for license
+
+typedef uint8_t byte;
+
+// Make loop iteration take us total, including cyc overhead of loop logic
+#define delay_loop_usec( us, cyc ) \
+	__builtin_avr_delay_cycles( (unsigned long) (F_CPU / 1e6 * (us) + 0.5) - (cyc) )
+
+#if !defined(ADB_PORT) || \
+	!defined(ADB_PIN)  || \
+	!defined(ADB_DDR)  || \
+	!defined(ADB_DATA_BIT)
+	#error
+#endif
+
+enum { data_mask = 1<<ADB_DATA_BIT };
+
+enum { adb_cmd_read  = 0x2C };
+enum { adb_cmd_write = 0x28 };
+
+// gcc is very unreliable for inlining, so use macros
+#define data_lo() (ADB_DDR |= data_mask)
+#define data_hi() (ADB_DDR &= ~data_mask)
+#define data_in() (ADB_PIN & data_mask)
+
+static void place_bit( byte bit )
+{
+	// 100 us bit cell time
+	data_lo();
+	_delay_us( 35 );
+	
+	// Difference between a 0 and 1 bit is just this 30us portion in the middle
+	if ( bit )
+		data_hi();
+	_delay_us( 30 );
+	
+	data_hi();
+	_delay_us( 35 );
+}
+
+static void place_bit0( void ) { place_bit( 0 ); }
+static void place_bit1( void ) { place_bit( 1 ); }
+
+static void send_byte( byte data )
+{
+	for ( byte n = 8; n; n-- )
+	{
+		place_bit( data & 0x80 );
+		data <<= 1;
+	}
+}
+
+static void command( byte cmd )
+{
+	data_lo();
+	_delay_us( 800 );
+	place_bit1();
+	send_byte( cmd );
+	place_bit0();
+}
+
+void adb_host_init( void )
+{
+	// Always keep port output 0, then just toggle DDR to be GND or leave it floating (high).
+	ADB_DDR	 &= ~data_mask;
+	ADB_PORT &= ~data_mask;
+	
+	#ifdef ADB_PSW_BIT
+		// Weak pull-up
+		ADB_PORT |=  (1<<ADB_PSW_BIT);
+		ADB_DDR  &= ~(1<<ADB_PSW_BIT);
+	#endif
+}
+
+bool adb_host_psw( void )
+{
+	#ifdef ADB_PSW_BIT
+		return (ADB_PIN & (1<<ADB_PSW_BIT)) != 0;
+	#else
+		return true;
+	#endif
+}
+
+// Waits while data == val, or until us timeout expires. Returns remaining time,
+// zero if timed out.
+static byte while_data( byte us, byte data )
+{
+	while ( data_in() == data )
+	{
+		delay_loop_usec( 1 /* us period */, 7 /* cycles loop overhead */ );
+		if ( !--us )
+			break;
+	}
+	return us;
+}
+
+static byte while_lo( byte us ) { return while_data( us, 0 ); }
+static byte while_hi( byte us ) { return while_data( us, data_mask ); }
+
+static uint16_t adb_host_talk( byte cmd )
+{
+	command( cmd );
+	_delay_us( 5 );
+	if ( !while_hi( 260 - 5 ) ) // avg 160
+		return adb_host_nothing;
+	
+	// Receive start bit and 16 data bits.
+	// Doing them all in loop allows consistent error checking
+	uint16_t data = 0;
+	byte n = 17;
+	do
+	{
+		data <<= 1;
+		enum { timeout = 130 }; // maximum bit cell time
+		
+		byte lo = while_lo( timeout );
+		if ( !lo )
+			goto error; // timeout
+		
+		byte hi = while_hi( lo );
+		if ( !hi )
+			goto error; // timeout
+		
+		if ( timeout-lo < lo-hi )
+			data |= 1;
+		else if ( n == 17 )
+			goto error; // start bit is wrong
+	}
+	while ( --n );
+	
+	// duration must be split in two due to 255 limit
+	if ( !while_lo( 255 ) && !while_lo( 351 - 255 ) )
+		goto error;
+	
+	if ( while_hi( 91 ) )
+		goto error;
+	
+	return data;
+	
+error:
+	return adb_host_error;
+}
+
+uint16_t adb_host_kbd_recv( void )
+{
+	return adb_host_talk( adb_cmd_read + 0 );
+}
+
+uint16_t adb_host_kbd_modifiers( void )
+{
+	return adb_host_talk( adb_cmd_read + 2 );
+}
+
+void adb_host_listen( byte cmd, byte data_h, byte data_l )
+{
+	command( cmd );
+	_delay_us( 200 );
+	
+	place_bit1();
+	send_byte( data_h ); 
+	send_byte( data_l );
+	place_bit0();
+}
+
+void adb_host_kbd_led( byte led )
+{
+	adb_host_listen( adb_cmd_write + 2, 0, led & 0x07 );
+}
+
+/* This software is licensed with a Modified BSD License.
+All of this is supposed to be Free Software, Open Source, DFSG-free,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE. */