2011-02-20 08:46:02 +00:00
/*
2011-07-20 15:32:52 +00:00
Copyright 2010 , 2011 Jun WAKO < wakojun @ gmail . com >
2011-02-20 08:46:02 +00:00
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 .
*/
2011-07-20 15:32:52 +00:00
2011-02-20 08:46:02 +00:00
/*
Primitive PS / 2 Library for AVR
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Host side is only supported now .
Synchronous USART is used to receive data by hardware process
rather than interrupt . During V - USB interrupt runs , CLOCK interrupt
cannot interpose . In the result it is prone to lost CLOCK edge .
I / O control
- - - - - - - - - - -
High state is asserted by internal pull - up .
If you have a signaling problem , you may need to have
external pull - up resisters on CLOCK and DATA line .
PS / 2 References
- - - - - - - - - - - - - - -
http : //www.computer-engineering.org/ps2protocol/
http : //www.mcamafia.de/pdf/ibm_hitrc07.pdf
*/
# include <stdbool.h>
# include <avr/io.h>
# include <avr/interrupt.h>
# include <util/delay.h>
# include "ps2.h"
# include "debug.h"
#if 0
# define DEBUGP_INIT() do { DDRC = 0xFF; } while (0)
# define DEBUGP(x) do { PORTC = x; } while (0)
# else
# define DEBUGP_INIT()
# define DEBUGP(x)
# 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 void clock_lo ( void ) ;
static inline void clock_hi ( void ) ;
static inline bool clock_in ( void ) ;
static inline void data_lo ( void ) ;
static inline void data_hi ( void ) ;
static inline bool data_in ( void ) ;
static inline uint16_t wait_clock_lo ( uint16_t us ) ;
static inline uint16_t wait_clock_hi ( uint16_t us ) ;
static inline uint16_t wait_data_lo ( uint16_t us ) ;
static inline uint16_t wait_data_hi ( uint16_t us ) ;
static inline void idle ( void ) ;
static inline void inhibit ( void ) ;
static inline uint8_t pbuf_dequeue ( void ) ;
static inline void pbuf_enqueue ( uint8_t data ) ;
void ps2_host_init ( void )
{
DEBUGP_INIT ( ) ;
DEBUGP ( 0x1 ) ;
idle ( ) ;
PS2_USART_INIT ( ) ;
PS2_USART_RX_INT_ON ( ) ;
}
uint8_t ps2_host_send ( uint8_t data )
{
uint8_t res = 0 ;
bool parity = true ;
ps2_error = PS2_ERR_NONE ;
DEBUGP ( 0x6 ) ;
PS2_USART_OFF ( ) ;
/* terminate a transmission if we have */
inhibit ( ) ;
_delay_us ( 100 ) ;
/* start bit [1] */
data_lo ( ) ;
clock_hi ( ) ;
WAIT ( clock_lo , 15000 , 1 ) ;
/* data [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 [10] */
_delay_us ( 15 ) ;
if ( parity ) { data_hi ( ) ; } else { data_lo ( ) ; }
WAIT ( clock_hi , 50 , 4 ) ;
WAIT ( clock_lo , 50 , 5 ) ;
/* stop bit [11] */
_delay_us ( 15 ) ;
data_hi ( ) ;
/* ack [12] */
WAIT ( data_lo , 50 , 6 ) ;
WAIT ( clock_lo , 50 , 7 ) ;
/* wait for idle state */
WAIT ( clock_hi , 50 , 8 ) ;
WAIT ( data_hi , 50 , 9 ) ;
res = ps2_host_recv_response ( ) ;
ERROR :
idle ( ) ;
PS2_USART_INIT ( ) ;
PS2_USART_RX_INT_ON ( ) ;
return res ;
}
// Do polling data from keyboard to get response to last command.
uint8_t ps2_host_recv_response ( void )
{
uint8_t data = 0 ;
PS2_USART_INIT ( ) ;
PS2_USART_RX_POLL_ON ( ) ;
while ( ! PS2_USART_RX_READY )
;
data = PS2_USART_RX_DATA ;
PS2_USART_OFF ( ) ;
DEBUGP ( 0x9 ) ;
return data ;
}
uint8_t ps2_host_recv ( void )
{
return pbuf_dequeue ( ) ;
}
ISR ( PS2_USART_RX_VECT )
{
DEBUGP ( 0x7 ) ;
uint8_t error = PS2_USART_ERROR ;
uint8_t data = PS2_USART_RX_DATA ;
if ( error ) {
DEBUGP ( error > > 2 ) ;
} else {
pbuf_enqueue ( data ) ;
}
DEBUGP ( 0x8 ) ;
}
/* send LED state to keyboard */
void ps2_host_set_led ( uint8_t led )
{
// send 0xED then keyboard keeps waiting for next LED data
// and keyboard does not send any scan codes during waiting.
// If fail to send LED data keyboard looks like being freezed.
uint8_t retry = 3 ;
while ( retry - - & & ps2_host_send ( PS2_SET_LED ) ! = PS2_ACK )
;
retry = 3 ;
while ( retry - - & & ps2_host_send ( led ) ! = PS2_ACK )
;
}
/*--------------------------------------------------------------------
* static functions
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
static inline void clock_lo ( )
{
PS2_CLOCK_PORT & = ~ ( 1 < < PS2_CLOCK_BIT ) ;
PS2_CLOCK_DDR | = ( 1 < < PS2_CLOCK_BIT ) ;
}
static inline void clock_hi ( )
{
/* input with pull up */
PS2_CLOCK_DDR & = ~ ( 1 < < PS2_CLOCK_BIT ) ;
PS2_CLOCK_PORT | = ( 1 < < PS2_CLOCK_BIT ) ;
}
static inline bool clock_in ( )
{
PS2_CLOCK_DDR & = ~ ( 1 < < PS2_CLOCK_BIT ) ;
PS2_CLOCK_PORT | = ( 1 < < PS2_CLOCK_BIT ) ;
_delay_us ( 1 ) ;
return PS2_CLOCK_PIN & ( 1 < < PS2_CLOCK_BIT ) ;
}
static inline void data_lo ( )
{
PS2_DATA_PORT & = ~ ( 1 < < PS2_DATA_BIT ) ;
PS2_DATA_DDR | = ( 1 < < PS2_DATA_BIT ) ;
}
static inline void data_hi ( )
{
/* input with pull up */
PS2_DATA_DDR & = ~ ( 1 < < PS2_DATA_BIT ) ;
PS2_DATA_PORT | = ( 1 < < PS2_DATA_BIT ) ;
}
static inline bool data_in ( )
{
PS2_DATA_DDR & = ~ ( 1 < < PS2_DATA_BIT ) ;
PS2_DATA_PORT | = ( 1 < < PS2_DATA_BIT ) ;
_delay_us ( 1 ) ;
return PS2_DATA_PIN & ( 1 < < PS2_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 */
static inline void inhibit ( void )
{
clock_lo ( ) ;
data_hi ( ) ;
}
/*--------------------------------------------------------------------
* Ring buffer to store scan codes from keyboard
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
# define PBUF_SIZE 8
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 )
{
if ( ! data )
return ;
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 {
debug ( " 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 ;
}