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Merge blargg's fix into adb.c

- <http://geekhack.org/index.php?topic=14290.msg1075201#msg1075201>
This commit is contained in:
tmk 2013-10-14 23:37:05 +09:00
parent 060f222c77
commit 98a6519a61

View File

@ -1,5 +1,6 @@
/*
Copyright 2011 Jun WAKO <wakojun@gmail.com>
Copyright 2013 Shay Green <gblargg@gmail.com>
This software is licensed with a Modified BSD License.
All of this is supposed to be Free Software, Open Source, DFSG-free,
@ -43,9 +44,11 @@ POSSIBILITY OF SUCH DAMAGE.
#include "debug.h"
static inline void data_lo(void);
static inline void data_hi(void);
static inline bool data_in(void);
// GCC doesn't inline functions normally
#define data_lo() (ADB_DDR |= (1<<ADB_DATA_BIT))
#define data_hi() (ADB_DDR &= ~(1<<ADB_DATA_BIT))
#define data_in() (ADB_PIN & (1<<ADB_DATA_BIT))
#ifdef ADB_PSW_BIT
static inline void psw_lo(void);
static inline void psw_hi(void);
@ -56,24 +59,17 @@ static inline void attention(void);
static inline void place_bit0(void);
static inline void place_bit1(void);
static inline void send_byte(uint8_t data);
static inline bool read_bit(void);
static inline uint8_t read_byte(void);
static inline uint8_t wait_data_lo(uint16_t us);
static inline uint8_t wait_data_hi(uint8_t us);
static inline uint16_t wait_data_lo(uint16_t us);
static inline uint16_t wait_data_hi(uint16_t us);
void adb_host_init(void)
{
ADB_PORT &= ~(1<<ADB_DATA_BIT);
data_hi();
#ifdef ADB_PSW_BIT
psw_hi();
#endif
// Enable keyboard left/right modifier distinction
// Addr:Keyboard(0010), Cmd:Listen(10), Register3(11)
// upper byte: reserved bits 0000, device address 0010
// lower byte: device handler 00000011
adb_host_listen(0x2B,0x02,0x03);
}
#ifdef ADB_PSW_BIT
@ -91,6 +87,41 @@ bool adb_host_psw(void)
* <http://geekhack.org/index.php?topic=14290.msg1068919#msg1068919>
* <http://geekhack.org/index.php?topic=14290.msg1070139#msg1070139>
*/
// ADB Bit Cells
//
// bit cell time: 70-130us
// low part of bit0: 60-70% of bit cell
// low part of bit1: 30-40% of bit cell
//
// bit cell time 70us 130us
// --------------------------------------------
// low part of bit0 42-49 78-91
// high part of bit0 21-28 39-52
// low part of bit1 21-28 39-52
// high part of bit1 42-49 78-91
//
//
// bit0:
// 70us bit cell:
// ____________~~~~~~
// 42-49 21-28
//
// 130us bit cell:
// ____________~~~~~~
// 78-91 39-52
//
// bit1:
// 70us bit cell:
// ______~~~~~~~~~~~~
// 21-28 42-49
//
// 130us bit cell:
// ______~~~~~~~~~~~~
// 39-52 78-91
//
// [from Apple IIgs Hardware Reference Second Edition]
uint16_t adb_host_kbd_recv(void)
{
uint16_t data = 0;
@ -100,24 +131,50 @@ uint16_t adb_host_kbd_recv(void)
if (!wait_data_lo(500)) { // Tlt/Stop to Start(140-260us)
return 0; // No data to send
}
if (!read_bit()) { // Startbit(1)
// Service Request
dprintf("Startbit ERROR\n");
return -2;
}
// ad hoc fix: without block inerrupt read wrong bit occasionally and get keys stuck
cli();
data = read_byte();
data = (data<<8) | read_byte();
uint8_t stop = read_bit(); // Stopbit(0)
sei();
// TODO: is this needed anymore with improved timing?
//cli();
uint8_t n = 17; // start bit + 16 data bits
do {
uint8_t lo = (uint8_t) wait_data_hi(130);
if (!lo)
goto error;
uint8_t hi = (uint8_t) wait_data_lo(lo);
if (!hi)
goto error;
hi = lo - hi;
lo = 130 - lo;
data <<= 1;
if (lo < hi) {
data |= 1;
}
else if (n == 17) {
// Service Request
dprintf("Startbit ERROR\n");
sei();
return -2;
}
}
while ( --n );
if (stop) {
// Stop bit can't be checked normally since it could have service request lenghtening
// and its high state never goes low.
if (!wait_data_hi(351) || wait_data_lo(91)) {
dprintf("Stopbit ERROR\n");
sei();
return -3;
}
sei();
return data;
error:
dprintf("Bit ERROR\n");
sei();
return -4;
}
void adb_host_listen(uint8_t cmd, uint8_t data_h, uint8_t data_l)
@ -142,23 +199,6 @@ void adb_host_kbd_led(uint8_t led)
}
static inline void data_lo()
{
ADB_DDR |= (1<<ADB_DATA_BIT);
ADB_PORT &= ~(1<<ADB_DATA_BIT);
}
static inline void data_hi()
{
ADB_PORT |= (1<<ADB_DATA_BIT);
ADB_DDR &= ~(1<<ADB_DATA_BIT);
}
static inline bool data_in()
{
ADB_PORT |= (1<<ADB_DATA_BIT);
ADB_DDR &= ~(1<<ADB_DATA_BIT);
return ADB_PIN&(1<<ADB_DATA_BIT);
}
#ifdef ADB_PSW_BIT
static inline void psw_lo()
{
@ -181,7 +221,7 @@ static inline bool psw_in()
static inline void attention(void)
{
data_lo();
_delay_us(700);
_delay_us(800-35); // bit1 holds lo for 35 more
place_bit1();
}
@ -211,81 +251,27 @@ static inline void send_byte(uint8_t data)
}
}
static inline bool read_bit(void)
// These are carefully coded to take 6 cycles of overhead.
// inline asm approach became too convoluted
static inline uint16_t wait_data_lo(uint16_t us)
{
// ADB Bit Cells
//
// bit cell time: 70-130us
// low part of bit0: 60-70% of bit cell
// low part of bit1: 30-40% of bit cell
//
// bit cell time 70us 130us
// --------------------------------------------
// low part of bit0 42-49 78-91
// high part of bit0 21-28 39-52
// low part of bit1 21-28 39-52
// high part of bit1 42-49 78-91
//
//
// bit0:
// 70us bit cell:
// ____________~~~~~~
// 42-49 21-28
//
// 130us bit cell:
// ____________~~~~~~
// 78-91 39-52
//
// bit1:
// 70us bit cell:
// ______~~~~~~~~~~~~
// 21-28 42-49
//
// 130us bit cell:
// ______~~~~~~~~~~~~
// 39-52 78-91
//
// read:
// ________|~~~~~~~~~
// 55us
// Read data line after 55us. If data line is low/high then bit is 0/1.
// This method might not work at <90us bit cell time.
//
// [from Apple IIgs Hardware Reference Second Edition]
bool bit;
wait_data_lo(75); // wait the start of bit cell at least 130ms(55+0+75)
_delay_us(55);
bit = data_in();
wait_data_hi(36); // wait high part of bit cell at least 91ms(55+36)
return bit;
}
static inline uint8_t read_byte(void)
{
uint8_t data = 0;
for (int i = 0; i < 8; i++) {
data <<= 1;
if (read_bit())
data = data | 1;
}
return data;
}
static inline uint8_t wait_data_lo(uint16_t us)
{
while (data_in() && us) {
_delay_us(1);
us--;
do {
if ( !data_in() )
break;
_delay_us(1 - (6 * 1000000.0 / F_CPU));
}
while ( --us );
return us;
}
static inline uint8_t wait_data_hi(uint8_t us)
static inline uint16_t wait_data_hi(uint16_t us)
{
while (!data_in() && us) {
_delay_us(1);
us--;
do {
if ( data_in() )
break;
_delay_us(1 - (6 * 1000000.0 / F_CPU));
}
while ( --us );
return us;
}