diff options
Diffstat (limited to 'platforms/avr/drivers/ps2/ps2_usart.c')
| -rw-r--r-- | platforms/avr/drivers/ps2/ps2_usart.c | 227 | 
1 files changed, 227 insertions, 0 deletions
| diff --git a/platforms/avr/drivers/ps2/ps2_usart.c b/platforms/avr/drivers/ps2/ps2_usart.c new file mode 100644 index 0000000000..151cfcd68f --- /dev/null +++ b/platforms/avr/drivers/ps2/ps2_usart.c @@ -0,0 +1,227 @@ +/* +Copyright 2010,2011,2012,2013 Jun WAKO <[email protected]> + +This software is licensed with a Modified BSD License. +All of this is supposed to be Free Software, Open Source, DFSG-free, +GPL-compatible, and OK to use in both free and proprietary applications. +Additions and corrections to this file are welcome. + + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + +* Redistributions of source code must retain the above copyright +  notice, this list of conditions and the following disclaimer. + +* Redistributions in binary form must reproduce the above copyright +  notice, this list of conditions and the following disclaimer in +  the documentation and/or other materials provided with the +  distribution. + +* Neither the name of the copyright holders nor the names of +  contributors may be used to endorse or promote products derived +  from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. +*/ + +/* + * PS/2 protocol USART version + */ + +#include <stdbool.h> +#include <avr/interrupt.h> +#include <util/delay.h> +#include "gpio.h" +#include "ps2.h" +#include "ps2_io.h" +#include "print.h" + +#ifndef PS2_CLOCK_DDR +#    define PS2_CLOCK_DDR PORTx_ADDRESS(PS2_CLOCK_PIN) +#endif +#ifndef PS2_CLOCK_BIT +#    define PS2_CLOCK_BIT (PS2_CLOCK_PIN & 0xF) +#endif +#ifndef PS2_DATA_DDR +#    define PS2_DATA_DDR PORTx_ADDRESS(PS2_DATA_PIN) +#endif +#ifndef PS2_DATA_BIT +#    define PS2_DATA_BIT (PS2_DATA_PIN & 0xF) +#endif + +#define WAIT(stat, us, err)     \ +    do {                        \ +        if (!wait_##stat(us)) { \ +            ps2_error = err;    \ +            goto ERROR;         \ +        }                       \ +    } while (0) + +uint8_t ps2_error = PS2_ERR_NONE; + +static inline uint8_t pbuf_dequeue(void); +static inline void    pbuf_enqueue(uint8_t data); +static inline bool    pbuf_has_data(void); +static inline void    pbuf_clear(void); + +void ps2_host_init(void) { +    idle();  // without this many USART errors occur when cable is disconnected +    PS2_USART_INIT(); +    PS2_USART_RX_INT_ON(); +    // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20) +    //_delay_ms(2500); +} + +uint8_t ps2_host_send(uint8_t data) { +    bool parity = true; +    ps2_error   = PS2_ERR_NONE; + +    PS2_USART_OFF(); + +    /* terminate a transmission if we have */ +    inhibit(); +    _delay_us(100);  // [4]p.13 + +    /* 'Request to Send' and Start bit */ +    data_lo(); +    clock_hi(); +    WAIT(clock_lo, 10000, 10);  // 10ms [5]p.50 + +    /* Data bit[2-9] */ +    for (uint8_t i = 0; i < 8; i++) { +        _delay_us(15); +        if (data & (1 << i)) { +            parity = !parity; +            data_hi(); +        } else { +            data_lo(); +        } +        WAIT(clock_hi, 50, 2); +        WAIT(clock_lo, 50, 3); +    } + +    /* Parity bit */ +    _delay_us(15); +    if (parity) { +        data_hi(); +    } else { +        data_lo(); +    } +    WAIT(clock_hi, 50, 4); +    WAIT(clock_lo, 50, 5); + +    /* Stop bit */ +    _delay_us(15); +    data_hi(); + +    /* Ack */ +    WAIT(data_lo, 50, 6); +    WAIT(clock_lo, 50, 7); + +    /* wait for idle state */ +    WAIT(clock_hi, 50, 8); +    WAIT(data_hi, 50, 9); + +    idle(); +    PS2_USART_INIT(); +    PS2_USART_RX_INT_ON(); +    return ps2_host_recv_response(); +ERROR: +    idle(); +    PS2_USART_INIT(); +    PS2_USART_RX_INT_ON(); +    return 0; +} + +uint8_t ps2_host_recv_response(void) { +    // Command may take 25ms/20ms at most([5]p.46, [3]p.21) +    uint8_t retry = 25; +    while (retry-- && !pbuf_has_data()) { +        _delay_ms(1); +    } +    return pbuf_dequeue(); +} + +uint8_t ps2_host_recv(void) { +    if (pbuf_has_data()) { +        ps2_error = PS2_ERR_NONE; +        return pbuf_dequeue(); +    } else { +        ps2_error = PS2_ERR_NODATA; +        return 0; +    } +} + +ISR(PS2_USART_RX_VECT) { +    // TODO: request RESEND when error occurs? +    uint8_t error = PS2_USART_ERROR;  // USART error should be read before data +    uint8_t data  = PS2_USART_RX_DATA; +    if (!error) { +        pbuf_enqueue(data); +    } else { +        xprintf("PS2 USART error: %02X data: %02X\n", error, data); +    } +} + +/* send LED state to keyboard */ +void ps2_host_set_led(uint8_t led) { +    ps2_host_send(0xED); +    ps2_host_send(led); +} + +/*-------------------------------------------------------------------- + * Ring buffer to store scan codes from keyboard + *------------------------------------------------------------------*/ +#define PBUF_SIZE 32 +static uint8_t     pbuf[PBUF_SIZE]; +static uint8_t     pbuf_head = 0; +static uint8_t     pbuf_tail = 0; +static inline void pbuf_enqueue(uint8_t data) { +    uint8_t sreg = SREG; +    cli(); +    uint8_t next = (pbuf_head + 1) % PBUF_SIZE; +    if (next != pbuf_tail) { +        pbuf[pbuf_head] = data; +        pbuf_head       = next; +    } else { +        print("pbuf: full\n"); +    } +    SREG = sreg; +} +static inline uint8_t pbuf_dequeue(void) { +    uint8_t val = 0; + +    uint8_t sreg = SREG; +    cli(); +    if (pbuf_head != pbuf_tail) { +        val       = pbuf[pbuf_tail]; +        pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE; +    } +    SREG = sreg; + +    return val; +} +static inline bool pbuf_has_data(void) { +    uint8_t sreg = SREG; +    cli(); +    bool has_data = (pbuf_head != pbuf_tail); +    SREG          = sreg; +    return has_data; +} +static inline void pbuf_clear(void) { +    uint8_t sreg = SREG; +    cli(); +    pbuf_head = pbuf_tail = 0; +    SREG                  = sreg; +} | 
