1 #ifndef _MC6821_H_
2 #define _MC6821_H_
3
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
19 #ifndef PIA_REG_PADWIDTH
20 #define PIA_REG_PADWIDTH 255
21 #endif
22
23 struct pia {
24 union {
25 volatile u_char pra;
26 volatile u_char ddra;
27 } ua;
28 u_char pad1[PIA_REG_PADWIDTH];
29 volatile u_char cra;
30 u_char pad2[PIA_REG_PADWIDTH];
31 union {
32 volatile u_char prb;
33 volatile u_char ddrb;
34 } ub;
35 u_char pad3[PIA_REG_PADWIDTH];
36 volatile u_char crb;
37 u_char pad4[PIA_REG_PADWIDTH];
38 };
39
40 #define ppra ua.pra
41 #define pddra ua.ddra
42 #define pprb ub.prb
43 #define pddrb ub.ddrb
44
45 #define PIA_C1_ENABLE_IRQ (1<<0)
46 #define PIA_C1_LOW_TO_HIGH (1<<1)
47 #define PIA_DDR (1<<2)
48 #define PIA_IRQ2 (1<<6)
49 #define PIA_IRQ1 (1<<7)
50
51 #endif
52
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