Tag: ds3231

Adds an inexpensive battery-backed real-time clock to a Commodore 64 through the user or cassette port.

The current project page provides version 1.0 software and exact wiring for three C64 connection choices. Gregory Nacu's i2c6502 source independently documents the C64 user-port PB2/PB3 implementation and DS3231 example under the MIT license. A generic RTC module, connector or pass-through board, wire, and battery are separate. Many inexpensive modules include a charging circuit intended for a rechargeable cell; follow the project's component-removal instructions before substituting a CR2032 or CR1225 primary cell. The Timo Voutilainen package does not state a hardware fabrication or software license.

Adds a battery-backed DS3231 clock, external LED time display, date display, and timer to a Commodore 64.

The Tindie page listed Clockwork64 at USD 38 but had ordering paused while the seller takes a break through July 31, 2026. It calls this the final batch before retirement, so confirm that an order can still be placed after the seller returns. A CR2032 is included. The maker reports compatibility problems with modern J-CIA replacement chips and directs buyers to version 0.2 of Timo Voutilainen's RTC software.

Adds a software-controlled FM receiver to a Commodore 64 or 128 through the user port, with an optional real-time clock and station storage.

Protovision showed eight units in stock with a one- to two-week shipping estimate on 2026-07-29. The optional DS3231 module and its CR2032 or LIR2032 battery are not included. The seller says the supplied software is incompatible with SD2IEC and similar devices and strongly recommends an original disk drive.