mc6821.h 1.2 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _MC6821_H_
  3. #define _MC6821_H_
  4. /*
  5. * This file describes the memery mapping of the MC6821 PIA.
  6. * The unions describe overlayed registers. Which of them is used is
  7. * determined by bit 2 of the corresponding control register.
  8. * this files expects the PIA_REG_PADWIDTH to be defined the numeric
  9. * value of the register spacing.
  10. *
  11. * Data came from MFC-31-Developer Kit (from Ralph Seidel,
  12. * zodiac@darkness.gun.de) and Motorola Data Sheet (from
  13. * Richard Hirst, srh@gpt.co.uk)
  14. *
  15. * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
  16. *
  17. */
  18. #ifndef PIA_REG_PADWIDTH
  19. #define PIA_REG_PADWIDTH 255
  20. #endif
  21. struct pia {
  22. union {
  23. volatile u_char pra;
  24. volatile u_char ddra;
  25. } ua;
  26. u_char pad1[PIA_REG_PADWIDTH];
  27. volatile u_char cra;
  28. u_char pad2[PIA_REG_PADWIDTH];
  29. union {
  30. volatile u_char prb;
  31. volatile u_char ddrb;
  32. } ub;
  33. u_char pad3[PIA_REG_PADWIDTH];
  34. volatile u_char crb;
  35. u_char pad4[PIA_REG_PADWIDTH];
  36. };
  37. #define ppra ua.pra
  38. #define pddra ua.ddra
  39. #define pprb ub.prb
  40. #define pddrb ub.ddrb
  41. #define PIA_C1_ENABLE_IRQ (1<<0)
  42. #define PIA_C1_LOW_TO_HIGH (1<<1)
  43. #define PIA_DDR (1<<2)
  44. #define PIA_IRQ2 (1<<6)
  45. #define PIA_IRQ1 (1<<7)
  46. #endif