hirestimer openMSX Team A peripheral of which only one was built (by Alex Wulms). It's a MSX cartridge containing a high resolution 32-bit counter. The counter ticks at 3.57MHz. It reacts to IO ports 0x20-0x23. Writing to any port resets the counter. Reading port 0x20 makes an internal copy of the value of the counter and returns the 8 lower bits of that copy. Reading ports 0x21-0x23 returns the other 3 bytes (from low to high) of this copy. sound expansion