git.sur5r.net Git - cc65/blob - include/_6522.h

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                  _6522.h                                  */
   4 /*                                                                           */
   5 /*                Internal include file, do not use directly                 */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2004 Stefan Haubenthal <polluks@sdf.lonestar.org>                     */
  10 /*                                                                           */
  11 /*                                                                           */
  12 /* This software is provided 'as-is', without any expressed or implied       */
  13 /* warranty.  In no event will the authors be held liable for any damages    */
  14 /* arising from the use of this software.                                    */
  15 /*                                                                           */
  16 /* Permission is granted to anyone to use this software for any purpose,     */
  17 /* including commercial applications, and to alter it and redistribute it    */
  18 /* freely, subject to the following restrictions:                            */
  19 /*                                                                           */
  20 /* 1. The origin of this software must not be misrepresented; you must not   */
  21 /*    claim that you wrote the original software. If you use this software   */
  22 /*    in a product, an acknowledgment in the product documentation would be  */
  23 /*    appreciated but is not required.                                       */
  24 /* 2. Altered source versions must be plainly marked as such, and must not   */
  25 /*    be misrepresented as being the original software.                      */
  26 /* 3. This notice may not be removed or altered from any source              */
  27 /*    distribution.                                                          */
  28 /*                                                                           */
  29 /*****************************************************************************/
  30
  31
  32
  33 #ifndef __VIA_H
  34 #define __VIA_H
  35
  36
  37
  38 /* Define a structure with the 6522 register offsets.
  39 ** NOTE: The timer registers are not declared as 16 bit registers, because
  40 ** the order in which the two 8 bit halves are written is important, and
  41 ** the compiler doesn't guarantee any order when writing 16 bit values.
  42 */
  43 struct __6522 {
  44     unsigned char       prb;            /* Port register B */
  45     unsigned char       pra;            /* Port register A */
  46     unsigned char       ddrb;           /* Data direction register B */
  47     unsigned char       ddra;           /* Data direction register A */
  48     unsigned char       t1_lo;          /* Timer 1, low byte */
  49     unsigned char       t1_hi;          /* Timer 1, high byte */
  50     unsigned char       t1l_lo;         /* Timer 1 latch, low byte */
  51     unsigned char       t1l_hi;         /* Timer 1 latch, high byte */
  52     unsigned char       t2_lo;          /* Timer 2, low byte */
  53     unsigned char       t2_hi;          /* Timer 2, high byte */
  54     unsigned char       sr;             /* Shift register */
  55     unsigned char       acr;            /* Auxiliary control register */
  56     unsigned char       pcr;            /* Peripheral control register */
  57     unsigned char       ifr;            /* Interrupt flag register */
  58     unsigned char       ier;            /* Interrupt enable register */
  59     unsigned char       pra2;           /* Port register A w/o handshake */
  60 };
  61
  62
  63
  64 /* End of _6522.h */
  65 #endif
  66
  67
  68