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