diff options
Diffstat (limited to 'protocol')
| -rw-r--r-- | protocol/adb.c | 208 |
1 files changed, 97 insertions, 111 deletions
diff --git a/protocol/adb.c b/protocol/adb.c index f706255ad..750f4b965 100644 --- a/protocol/adb.c +++ b/protocol/adb.c @@ -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) -{ - // 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) +// 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) { - 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; } |