u8g_com_atmega_sw_spi.c

00001 /*
00002   
00003   u8g_com_atmega_sw_spi.c
00004 
00005   Universal 8bit Graphics Library
00006   
00007   Copyright (c) 2012, olikraus@gmail.com
00008   All rights reserved.
00009 
00010   Redistribution and use in source and binary forms, with or without modification, 
00011   are permitted provided that the following conditions are met:
00012 
00013   * Redistributions of source code must retain the above copyright notice, this list 
00014     of conditions and the following disclaimer.
00015     
00016   * Redistributions in binary form must reproduce the above copyright notice, this 
00017     list of conditions and the following disclaimer in the documentation and/or other 
00018     materials provided with the distribution.
00019 
00020   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
00021   CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
00022   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00023   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
00024   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
00025   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
00026   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
00027   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
00028   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
00029   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
00030   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
00031   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
00032   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
00033   
00034 
00035 */
00036 
00037 #include "u8g.h"
00038 
00039 #if defined(__AVR__)
00040 
00041 static void u8g_atmega_sw_spi_shift_out(u8g_t *u8g, uint8_t val) U8G_NOINLINE;
00042 static void u8g_atmega_sw_spi_shift_out(u8g_t *u8g, uint8_t val)
00043 {
00044   uint8_t i = 8;
00045   do
00046   {
00047     u8g_SetPILevel(u8g, U8G_PI_MOSI, val & 128 );
00048     val <<= 1;
00049     u8g_SetPILevel(u8g, U8G_PI_SCK, 1 );
00050     u8g_MicroDelay();       /* 15 Aug 2012: added for high speed uC */
00051     u8g_SetPILevel(u8g, U8G_PI_SCK, 0 );
00052     u8g_MicroDelay();       /* 15 Aug 2012: added for high speed uC */
00053     i--;
00054   } while( i != 0 );
00055 }
00056 
00057 uint8_t u8g_com_atmega_sw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
00058 {
00059   switch(msg)
00060   {
00061     case U8G_COM_MSG_INIT:
00062       u8g_SetPIOutput(u8g, U8G_PI_SCK);
00063       u8g_SetPIOutput(u8g, U8G_PI_MOSI);
00064       u8g_SetPIOutput(u8g, U8G_PI_A0);
00065       u8g_SetPIOutput(u8g, U8G_PI_CS);
00066       u8g_SetPIOutput(u8g, U8G_PI_RESET);
00067       
00068       u8g_SetPILevel(u8g, U8G_PI_SCK, 0 );
00069       u8g_SetPILevel(u8g, U8G_PI_MOSI, 0 );
00070       u8g_SetPILevel(u8g, U8G_PI_CS, 1 );
00071       u8g_SetPILevel(u8g, U8G_PI_A0, 0);
00072       break;
00073     
00074     case U8G_COM_MSG_STOP:
00075       break;
00076 
00077     case U8G_COM_MSG_ADDRESS:                     /* define cmd (arg_val = 0) or data mode (arg_val = 1) */
00078       u8g_SetPILevel(u8g, U8G_PI_A0, arg_val);
00079       break;
00080 
00081     case U8G_COM_MSG_CHIP_SELECT:
00082       
00083       if ( arg_val == 0 )
00084       {
00085         /* disable */
00086         u8g_SetPILevel(u8g, U8G_PI_CS, 1);
00087       }
00088       else
00089       {
00090         u8g_SetPILevel(u8g, U8G_PI_SCK, 0 );
00091         /* enable */
00092         u8g_SetPILevel(u8g, U8G_PI_CS, 0); /* CS = 0 (low active) */
00093       }
00094       break;
00095       
00096     case U8G_COM_MSG_RESET:
00097       u8g_SetPILevel(u8g, U8G_PI_RESET, arg_val);
00098       break;
00099     
00100 
00101     case U8G_COM_MSG_WRITE_BYTE:
00102       u8g_atmega_sw_spi_shift_out(u8g, arg_val);
00103       break;
00104     
00105     case U8G_COM_MSG_WRITE_SEQ:
00106       {
00107         register uint8_t *ptr = arg_ptr;
00108         while( arg_val > 0 )
00109         {
00110           u8g_atmega_sw_spi_shift_out(u8g, *ptr++);
00111           arg_val--;
00112         }
00113       }
00114       break;
00115 
00116       case U8G_COM_MSG_WRITE_SEQ_P:
00117       {
00118         register uint8_t *ptr = arg_ptr;
00119         while( arg_val > 0 )
00120         {
00121           u8g_atmega_sw_spi_shift_out(u8g, u8g_pgm_read(ptr));
00122           ptr++;
00123           arg_val--;
00124         }
00125       }
00126       break;
00127   }
00128   return 1;
00129 }
00130 
00131 #else
00132 
00133 
00134 uint8_t u8g_com_atmega_sw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr)
00135 {
00136   return 1;
00137 }
00138 
00139 
00140 #endif
00141 
00142