I found it tedious to calculate the register values used in delay loops for my Intel 4004 Single Board Computer so I wrote this simple Delphi 7 application to do the calculations. The application assumes that you're using an Intel 4201 Clock Generator IC with a 5.185 MHz crystal operating in Mode 1 to generate the clock signals for your 4004 or 4040. In Mode 1, the 4201 divides the crystal frequency by seven. The crystal frequency can be changed to any value from 3500000 to 5185000 Hz in the lower left corner of the panel.

There are two ways to use the application.

1. You can experimentally manipulate the sliders for the R0-R3 registers in the center of the panel until you come up with the delay value that you're looking for. Or...
2. You can enter the desired delay (in microseconds) into the lower right corner of the panel and click the "Calculate" button.

Once you're satisfied, click the "Copy" button in the upper left corner of the panel to copy the delay loop code to the clipboard. Paste the delay loop code into your source file.

4004 Delay Calculator