Update cbm510.sgml

[cc65] / include / _pia.h

diff --git a/include/_pia.h b/include/_pia.h
index bd4f7c8baf665364bf5ae800cfa3ef7e48958251..4b71ecfd4a02f1d3c7294bb64d6e7a68cfbf6c1c 100644 (file)
--- a/include/_pia.h
+++ b/include/_pia.h
@@ -4,14 +4,13 @@
 /*                                                                           */
 /*                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"   */
+/* The Peripheral Interface Adapter (PIA) chip (a 6520 or 6820) provides     */
+/* parallel I/O interfacing; it was used in Atari 400/800 and Commodore PET  */
+/* family of computers, for joystick and some interrupts.                    */
+/* Sources; various + Wikpedia article on "Peripheral Interface Adapter".    */
 /*                                                                           */
 /*                                                                           */
 /* (C) 2000 Freddy Offenga <taf_offenga@yahoo.com>                           */
-/* 2019-01-13: Bill Kendrick <nbs@sonic.net>: Defines for registers          */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */
@@ -42,42 +41,12 @@
 /* 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*/
 };
 
-
+/* (Some specific register values for Atari defined in atari.h) */
 
 /* End of _pia.h */
 #endif