Qalle's Clock

A 24-hour 7-segment clock for the NES.

Table of contents:

• List of files
• Technical info
• How to use
  • Adjust mode
  • Run mode

List of files

Text

• assemble.sh: a Linux script that assembles the program (warning: deletes files)
• clock.asm: source code (assembles with ASM6)

Image

• chr.png: CHR data as an image (can be encoded with nes_chr_encode.py from my NES utilities)
• snap*.png: screenshots

Binary

• chr.bin.gz: CHR data in NES format (gzip compressed)
• clock.nes.gz: assembled program in iNES format (gzip compressed)

Technical info

• mapper: NROM
• PRG ROM: 8 KiB
• CHR ROM: 2 KiB
• name table mirroring: vertical
• compatibility: NTSC & PAL

How to use

There are two modes.

Adjust mode

• The program starts in this mode.
• Time does not advance.
• The clock is at the center of the screen.
• The cursor (up arrow) is visible.

Buttons:

• left/right: move cursor
• up/down: change digit at cursor
• select: toggle between NTSC and PAL timing
• start: switch to run mode (hour must be 23 or less)

Run mode

• If using NTSC timing, time advances by one second every 60.1 frames.
• If using PAL timing, time advances by one second every 50.008333… frames.
• The clock moves around the screen to prevent burn-in.
• The cursor is hidden.

Buttons:

• start: return to adjust mode