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
23struct 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