/*****************************************************************************/ /* */ /* _pia.h */ /* */ /* Internal include file, do not use directly */ /* */ /* The Peripheral Interface Adapter (PIA) chip provides parallel I/O */ /* interfacing; it was used in Atari 400/800 and Commodore PET family of */ /* computers, for joystick and interrupts. */ /* - Sources; various + Wikpedia article on "Peripheral Interface Adapter" */ /* */ /* */ /* (C) 2000 Freddy Offenga */ /* 2019-01-13: Bill Kendrick : Defines for registers */ /* */ /* */ /* This software is provided 'as-is', without any expressed or implied */ /* warranty. In no event will the authors be held liable for any damages */ /* arising from the use of this software. */ /* */ /* Permission is granted to anyone to use this software for any purpose, */ /* including commercial applications, and to alter it and redistribute it */ /* freely, subject to the following restrictions: */ /* */ /* 1. The origin of this software must not be misrepresented; you must not */ /* claim that you wrote the original software. If you use this software */ /* in a product, an acknowledgment in the product documentation would be */ /* appreciated but is not required. */ /* 2. Altered source versions must be plainly marked as such, and must not */ /* be misrepresented as being the original software. */ /* 3. This notice may not be removed or altered from any source */ /* distribution. */ /* */ /*****************************************************************************/ #ifndef __PIA_H #define __PIA_H /* Define a structure with the PIA register offsets */ struct __pia { unsigned char porta; /* port A data r/w */ /* Paddle 0-3 triggers (per PORTA bits) */ #define PORTA_PTRIG3 0x80 #define PORTA_PTRIG2 0x40 #define PORTA_PTRIG1 0x08 #define PORTA_PTRIG0 0x04 unsigned char portb; /* port B data r/w */ /* Paddle 4-7 triggers (per PORTB bits); only 400/800 had four controller ports */ #define PORTB_PTRIG7 0x80 #define PORTB_PTRIG6 0x40 #define PORTB_PTRIG5 0x08 #define PORTB_PTRIG4 0x04 /* See also: "JOY_xxx_MASK" in "atari.h" */ unsigned char pactl; /* port A control */ unsigned char pbctl; /* port B control */ #define PxCTL_IRQ_ENABLE 0x01 /* (W) Peripheral A interrupt (IRQ) enable. */ /* One equals enable. Set by the OS but available to the user; reset on powerup. */ #define PxCTL_BIT1 0x02 /* "Set to zero" */ #define PxCTL_ADDRESSING 0x04 /* (W) Controls PORTA addressing */ /* One equals PORTA register; zero equals direction control register */ #define PACTL_MOTOR_CONTROL 0x08 /* (W) Peripheral motor control line (turn the cassette on or off; zero equals on) */ #define PBCTL_PERIPH_CMD_IDENT 0x08 /* Peripheral command identification (serial bus command) */ #define PxCTL_BIT4 0x10 /* "Set to one" */ #define PxCTL_BIT5 0x20 /* "Set to one" */ #define PxCTL_BIT6 0x40 /* "Set to zero" */ #define PxCTL_IRQ_STATUS 0x80 /* Peripheral interrupt (IRQ) status bit. */ /* Set by Peripherals (PORTA / PORTB). Reset by reading PORTA / PORTB*/ }; /* End of _pia.h */ #endif