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- /*
-
- u8g_com_atmega_hw_spi.c
-
- Universal 8bit Graphics Library
-
- Copyright (c) 2012, olikraus@gmail.com
- All rights reserved.
-
- 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.
-
- 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 HOLDER 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.
-
-
- Assumes, that
- MOSI is at PORTB, Pin 3
- and
- SCK is at PORTB, Pin 5
-
- Update for ATOMIC operation done (01 Jun 2013)
- U8G_ATOMIC_OR(ptr, val)
- U8G_ATOMIC_AND(ptr, val)
- U8G_ATOMIC_START()
- U8G_ATOMIC_END()
-
-
-
- */
-
- #include "u8g.h"
-
-
- #if defined(__AVR__)
- #define U8G_ATMEGA_HW_SPI
-
- /* remove the definition for attiny */
- #if __AVR_ARCH__ == 2
- #undef U8G_ATMEGA_HW_SPI
- #endif
- #if __AVR_ARCH__ == 25
- #undef U8G_ATMEGA_HW_SPI
- #endif
- #endif
-
-
- #if defined(U8G_ATMEGA_HW_SPI)
-
- #include <avr/interrupt.h>
- #include <avr/io.h>
-
-
- static uint8_t u8g_atmega_spi_out(uint8_t data)
- {
- /* unsigned char x = 100; */
- /* send data */
- SPDR = data;
- /* wait for transmission */
- while (!(SPSR & (1<<SPIF)))
- ;
- /* clear the SPIF flag by reading SPDR */
- return SPDR;
- }
-
-
- uint8_t u8g_com_atmega_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
- {
- switch(msg)
- {
- case U8G_COM_MSG_STOP:
- break;
-
- case U8G_COM_MSG_INIT:
-
- u8g_SetPIOutput(u8g, U8G_PI_CS);
- u8g_SetPIOutput(u8g, U8G_PI_A0);
- u8g_SetPIOutput(u8g, U8G_PI_RESET);
-
- U8G_ATOMIC_START();
-
- DDRB |= _BV(3); /* D0, MOSI */
- DDRB |= _BV(5); /* SCK */
- DDRB |= _BV(2); /* slave select */
-
- PORTB &= ~_BV(3); /* D0, MOSI = 0 */
- PORTB &= ~_BV(5); /* SCK = 0 */
-
- U8G_ATOMIC_END();
-
- u8g_SetPILevel(u8g, U8G_PI_CS, 1);
-
- /*
- SPR1 SPR0
- 0 0 fclk/4 x
- 0 1 fclk/16
- 1 0 fclk/64
- 1 1 fclk/128
- */
- SPCR = 0;
- SPCR = (1<<SPE) | (1<<MSTR)|(0<<SPR1)|(0<<SPR0)|(0<<CPOL)|(0<<CPHA);
- #ifdef U8G_HW_SPI_2X
- SPSR = (1 << SPI2X); /* double speed, issue 89 */
- #endif
-
- break;
-
- case U8G_COM_MSG_ADDRESS: /* define cmd (arg_val = 0) or data mode (arg_val = 1) */
- u8g_SetPILevel(u8g, U8G_PI_A0, arg_val);
- break;
-
- case U8G_COM_MSG_CHIP_SELECT:
-
- if ( arg_val == 0 )
- {
- /* disable */
- u8g_SetPILevel(u8g, U8G_PI_CS, 1);
- }
- else
- {
- PORTB &= ~_BV(5); /* SCK = 0 */
- /* enable */
- u8g_SetPILevel(u8g, U8G_PI_CS, 0); /* CS = 0 (low active) */
- }
-
- break;
-
- case U8G_COM_MSG_RESET:
- u8g_SetPILevel(u8g, U8G_PI_RESET, arg_val);
- break;
-
- case U8G_COM_MSG_WRITE_BYTE:
- u8g_atmega_spi_out(arg_val);
- break;
-
- case U8G_COM_MSG_WRITE_SEQ:
- {
- register uint8_t *ptr = arg_ptr;
- while( arg_val > 0 )
- {
- u8g_atmega_spi_out(*ptr++);
- arg_val--;
- }
- }
- break;
- case U8G_COM_MSG_WRITE_SEQ_P:
- {
- register uint8_t *ptr = arg_ptr;
- while( arg_val > 0 )
- {
- u8g_atmega_spi_out(u8g_pgm_read(ptr));
- ptr++;
- arg_val--;
- }
- }
- break;
- }
- return 1;
- }
-
- #else
-
- uint8_t u8g_com_atmega_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
- {
- return 1;
- }
-
- #endif
-
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