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