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- #include <stdbool.h>
- #include <util/delay.h>
- #include <avr/io.h>
- #include "adb.h"
-
-
- static inline void data_lo(void);
- static inline void data_hi(void);
- static inline bool data_in(void);
- #ifdef ADB_PSW_BIT
- static inline void psw_lo(void);
- static inline void psw_hi(void);
- static inline bool psw_in(void);
- #endif
-
- 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(uint8_t us);
- static inline uint8_t wait_data_hi(uint8_t us);
-
-
- void adb_host_init(void)
- {
- data_hi();
- #ifdef ADB_PSW_BIT
- psw_hi();
- #endif
- }
-
- #ifdef ADB_PSW_BIT
- bool adb_host_psw(void)
- {
- return psw_in();
- }
- #endif
-
- uint16_t adb_host_kbd_recv(void)
- {
- uint16_t data = 0;
- attention();
- send_byte(0x2C); // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
- place_bit0(); // Stopbit(0)
- if (!wait_data_lo(0xFF)) // Tlt/Stop to Start(140-260us)
- return 0; // No data to send
- if (!read_bit()) // Startbit(1)
- return -2;
- data = read_byte();
- data = (data<<8) | read_byte();
- if (read_bit()) // Stopbit(0)
- return -3;
- return data;
- }
-
- // send state of LEDs
- void adb_host_kbd_led(uint8_t led)
- {
- attention();
- send_byte(0x2A); // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
- place_bit0(); // Stopbit(0)
- _delay_us(200); // Tlt/Stop to Start
- place_bit1(); // Startbit(1)
- send_byte(0); // send upper byte (not used)
- send_byte(led&0x07); // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0: NumLock)
- place_bit0(); // Stopbit(0);
- }
-
-
- 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()
- {
- ADB_DDR |= (1<<ADB_PSW_BIT);
- ADB_PORT &= ~(1<<ADB_PSW_BIT);
- }
- static inline void psw_hi()
- {
- ADB_PORT |= (1<<ADB_PSW_BIT);
- ADB_DDR &= ~(1<<ADB_PSW_BIT);
- }
- static inline bool psw_in()
- {
- ADB_PORT |= (1<<ADB_PSW_BIT);
- ADB_DDR &= ~(1<<ADB_PSW_BIT);
- return ADB_PIN&(1<<ADB_PSW_BIT);
- }
- #endif
-
- static inline void attention(void)
- {
- data_lo();
- _delay_us(700);
- place_bit1();
- }
-
- static inline void place_bit0(void)
- {
- data_lo();
- _delay_us(65);
- data_hi();
- _delay_us(35);
- }
-
- static inline void place_bit1(void)
- {
- data_lo();
- _delay_us(35);
- data_hi();
- _delay_us(65);
- }
-
- static inline void send_byte(uint8_t data)
- {
- for (int i = 0; i < 8; i++) {
- if (data&(0x80>>i))
- place_bit1();
- else
- place_bit0();
- }
- }
-
- static inline bool read_bit(void)
- {
- // ADB Bit Cells
- //
- // bit0: ______~~~
- // 65 :35us
- //
- // bit1: ___~~~~~~
- // 35 :65us
- //
- // bit0 low time: 60-70% of bit cell(42-91us)
- // bit1 low time: 30-40% of bit cell(21-52us)
- // bit cell time: 70-130us
- // [from Apple IIgs Hardware Reference Second Edition]
- //
- // After 55us if data line is low/high then bit is 0/1.
- // Too simple to rely on?
- bool bit;
- wait_data_lo(75); // wait the beginning of bit cell
- _delay_us(55);
- bit = data_in();
- wait_data_hi(36); // wait high part of bit cell
- 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(uint8_t us)
- {
- while (data_in() && us) {
- _delay_us(1);
- us--;
- }
- return us;
- }
-
- static inline uint8_t wait_data_hi(uint8_t us)
- {
- while (!data_in() && us) {
- _delay_us(1);
- us--;
- }
- return us;
- }
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