From 27dc9828238279243e4b5da75bde7bb45f1ea8ff Mon Sep 17 00:00:00 2001 From: "Tobias V. Langhoff" Date: Tue, 2 Jan 2024 16:05:28 +0100 Subject: [PATCH] Remove confusing and redundant wording (#519) * Remove confusing and redundant wording * Link to explanation of interrupt requesting --------- Co-authored-by: Eldred Habert --- src/Interrupt_Sources.md | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/src/Interrupt_Sources.md b/src/Interrupt_Sources.md index 8931de63..ce9d6f9e 100644 --- a/src/Interrupt_Sources.md +++ b/src/Interrupt_Sources.md @@ -2,7 +2,7 @@ ## INT $40 — VBlank interrupt -This interrupt is requested every time the Game Boy enters VBlank ([Mode 1](<#PPU modes>)). +This interrupt [is requested] every time the Game Boy enters VBlank ([Mode 1](<#PPU modes>)). The VBlank interrupt occurs ca. 59.7 times a second on a handheld Game Boy (DMG or CGB) or Game Boy Player and ca. 61.1 times a second on a @@ -20,7 +20,7 @@ The various STAT interrupt sources (modes 0-2 and LYC=LY) have their state (inactive=low and active=high) logically ORed into a shared "STAT interrupt line" if their respective enable bit is turned on. -A STAT interrupt will be triggered by a rising edge (transition from +A STAT interrupt [will be triggered][is requested] by a rising edge (transition from low to high) on the STAT interrupt line. :::warning STAT blocking @@ -52,10 +52,7 @@ hidden by the text box. ## INT $50 — Timer interrupt -Every time that the timer overflows (that is, when [TIMA](<#FF05 — TIMA: Timer counter>) exceeds $FF), -an interrupt is requested by setting bit 2 in the IF register -($FF0F). As soon as that interrupt is enabled, the CPU will execute it by -calling the timer interrupt vector at $0050. +The timer interrupt [is requested] every time that the timer overflows (that is, when [TIMA](<#FF05 — TIMA: Timer counter>) exceeds $FF). ## INT $58 — Serial interrupt @@ -98,7 +95,7 @@ clocked serial transfer does not exit STOP mode. ## INT $60 — Joypad interrupt -The Joypad interrupt is requested when any of [`P1`](<#FF00 — P1/JOYP: Joypad>) bits 0-3 change +The Joypad interrupt [is requested] when any of [`P1`](<#FF00 — P1/JOYP: Joypad>) bits 0-3 change from High to Low. This happens when a button is pressed (provided that the action/direction buttons are enabled by bit 5/4, respectively), however, due to switch bounce, one or more High to Low @@ -114,3 +111,5 @@ make no difference. The only meaningful purpose of the Joypad interrupt would be to terminate the STOP (low power) standby state. GBA SP, because of the different buttons used, seems to not be affected by switch bounce. + +[is requested]: <#FF0F — IF: Interrupt flag>