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/*
Copyright 2014 Jun WAKO <wakojun@gmail.com>
*/
#pragma once
#define IBM4704_ERR_NONE 0
#define IBM4704_ERR_PARITY 0x70
void ibm4704_init(void);
uint8_t ibm4704_send(uint8_t data);
uint8_t ibm4704_recv_response(void);
uint8_t ibm4704_recv(void);
/* Check pin configuration */
#if !(defined(IBM4704_CLOCK_PORT) && defined(IBM4704_CLOCK_PIN) && defined(IBM4704_CLOCK_DDR) && defined(IBM4704_CLOCK_BIT))
# error "ibm4704 clock pin configuration is required in config.h"
#endif
#if !(defined(IBM4704_DATA_PORT) && defined(IBM4704_DATA_PIN) && defined(IBM4704_DATA_DDR) && defined(IBM4704_DATA_BIT))
# error "ibm4704 data pin configuration is required in config.h"
#endif
/*--------------------------------------------------------------------
* static functions
*------------------------------------------------------------------*/
static inline void clock_lo(void) {
IBM4704_CLOCK_PORT &= ~(1 << IBM4704_CLOCK_BIT);
IBM4704_CLOCK_DDR |= (1 << IBM4704_CLOCK_BIT);
}
static inline void clock_hi(void) {
/* input with pull up */
IBM4704_CLOCK_DDR &= ~(1 << IBM4704_CLOCK_BIT);
IBM4704_CLOCK_PORT |= (1 << IBM4704_CLOCK_BIT);
}
static inline bool clock_in(void) {
IBM4704_CLOCK_DDR &= ~(1 << IBM4704_CLOCK_BIT);
IBM4704_CLOCK_PORT |= (1 << IBM4704_CLOCK_BIT);
_delay_us(1);
return IBM4704_CLOCK_PIN & (1 << IBM4704_CLOCK_BIT);
}
static inline void data_lo(void) {
IBM4704_DATA_PORT &= ~(1 << IBM4704_DATA_BIT);
IBM4704_DATA_DDR |= (1 << IBM4704_DATA_BIT);
}
static inline void data_hi(void) {
/* input with pull up */
IBM4704_DATA_DDR &= ~(1 << IBM4704_DATA_BIT);
IBM4704_DATA_PORT |= (1 << IBM4704_DATA_BIT);
}
static inline bool data_in(void) {
IBM4704_DATA_DDR &= ~(1 << IBM4704_DATA_BIT);
IBM4704_DATA_PORT |= (1 << IBM4704_DATA_BIT);
_delay_us(1);
return IBM4704_DATA_PIN & (1 << IBM4704_DATA_BIT);
}
static inline uint16_t wait_clock_lo(uint16_t us) {
while (clock_in() && us) {
asm("");
_delay_us(1);
us--;
}
return us;
}
static inline uint16_t wait_clock_hi(uint16_t us) {
while (!clock_in() && us) {
asm("");
_delay_us(1);
us--;
}
return us;
}
static inline uint16_t wait_data_lo(uint16_t us) {
while (data_in() && us) {
asm("");
_delay_us(1);
us--;
}
return us;
}
static inline uint16_t wait_data_hi(uint16_t us) {
while (!data_in() && us) {
asm("");
_delay_us(1);
us--;
}
return us;
}
/* idle state that device can send */
static inline void idle(void) {
clock_hi();
data_hi();
}
/* inhibit device to send
* keyboard checks Data line on start bit(Data:hi) and it stops sending if Data line is low.
*/
static inline void inhibit(void) {
clock_hi();
data_lo();
}
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