PCBgogo

*** No worries with PCBGOGO, the board in 12 days after online delivery of the files (Belgium). The quality is excellent and neat. The silk printing is fine and absolutely readable. Even the 2mm fonts are perfectly printed. If you have other than round holes PCBGOGO does the job nice and clean. All components fit snuggly without issues. I chose the standerd PCB material with a thickness of 1.6 mm which feels strong, very much usable as a frame for a loading carrying toy however that's not my intention. *** - The design foresaw in a fully accessible Z80 bus, MIDI interface and TTL COM interface. - Data protection for non-volatile functioning of the RAM. - (E)EPROM/RAM paging in steps of 2K with the bottom 2K fixed to (E)EPROM. - (E)EPROM up to 64K, RAM up to 64K configurable with jumpers according to capacities of memory chips used. - Wait state selectable for as well ROM as RAM (you never know). - Intel 8251 used as UART. UART TTL levels port separately accessible next to MIDI interface implementation of the data stream. - Z80 CPU system clock divider for /1, /2, /4 and /8. UART RxTx clock switchable by software between 2 available crystal time bases. - On board 12 volts to 5 volts stabilizer with diode polarization protection. 12 volts adapter socket and 12 volts connector. - Probably a practical basic computer system tool for educational purposes for nowadays since Arduinos are still kind of obscure in their design.