Intel 4004 and 4040 4-bit processor development kit with Busicom 141-PF calculator emulation

"Practical Electronics" magazine article on building "Champ" 4040 microcomputer

Decimal arithmetic subroutines for the Intel 4004 CPU

Single Board Computer using Intel 4040

Calculate register values for Intel 4004 and 4040 delay loops

A 16 bit random number generator for the Intel 4004 or 4040 CPU

A clock divider module that uses 4040 chip. It divides by 2; 4; 8; 16; 32; 64; 128; 226; 512; 1024; 2048; 4096.