The PD17240, 17241, 17242, 17243, 17244, 17245, 17246 (hereafter called the PD17246 Subseries) are 4bit single-chip microcontrollers for small general-purpose infrared remote control transmitters. This subseries employs 17K general-purpose register system architecture for the CPU, and can directly execute operations between data memories instead of the conventional method of executing operations through an accumulator. Moreover, all the instructions are 16-bit/1-word instructions, enabling efficient programming. In addition, a one-time PROM model, the PD17P246, to which data can be written only once, is also available. This product is convenient either for evaluating the PD17246 Subseries programs or for small-scale production of application systems.