1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
#ifndef _MC6821_H_
|
|
#define _MC6821_H_
|
|
|
|
/*
|
|
* This file describes the memery mapping of the MC6821 PIA.
|
|
* The unions describe overlayed registers. Which of them is used is
|
|
* determined by bit 2 of the corresponding control register.
|
|
* this files expects the PIA_REG_PADWIDTH to be defined the numeric
|
|
* value of the register spacing.
|
|
*
|
|
* Data came from MFC-31-Developer Kit (from Ralph Seidel,
|
|
* zodiac@darkness.gun.de) and Motorola Data Sheet (from
|
|
* Richard Hirst, srh@gpt.co.uk)
|
|
*
|
|
* 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
|
|
*
|
|
*/
|
|
|
|
#ifndef PIA_REG_PADWIDTH
|
|
#define PIA_REG_PADWIDTH 255
|
|
#endif
|
|
|
|
struct pia {
|
|
union {
|
|
volatile u_char pra;
|
|
volatile u_char ddra;
|
|
} ua;
|
|
u_char pad1[PIA_REG_PADWIDTH];
|
|
volatile u_char cra;
|
|
u_char pad2[PIA_REG_PADWIDTH];
|
|
union {
|
|
volatile u_char prb;
|
|
volatile u_char ddrb;
|
|
} ub;
|
|
u_char pad3[PIA_REG_PADWIDTH];
|
|
volatile u_char crb;
|
|
u_char pad4[PIA_REG_PADWIDTH];
|
|
};
|
|
|
|
#define ppra ua.pra
|
|
#define pddra ua.ddra
|
|
#define pprb ub.prb
|
|
#define pddrb ub.ddrb
|
|
|
|
#define PIA_C1_ENABLE_IRQ (1<<0)
|
|
#define PIA_C1_LOW_TO_HIGH (1<<1)
|
|
#define PIA_DDR (1<<2)
|
|
#define PIA_IRQ2 (1<<6)
|
|
#define PIA_IRQ1 (1<<7)
|
|
|
|
#endif
|