The Forth Deck mini is a portable Forth computer with a discrete CPU, reminiscent of 70s and 80s home computers. It includes features like a 40 x 4 character LCD, 56-button QWERTY keyboard, rechargeable battery, and 8-bit CMOS logic CPU. Surprisingly, the LCD is driven in 4-bit mode using an I/O-port expander due to pin limitations. The explanation of the keyboard PCB design, utilizing a shift key for hardware resets, and software support in My4TH ROM for the keyboard board, is unique. Also, the LiPo battery uses a TP5400 charger circuit, making it user-friendly. Building instructions for the Forth Deck are available online.
http://mynor.org/my4th_forthdeck.htm