A down counter running at the xosc frequency which counts to zero and stops. Can be used for short software pauses when setting up time sensitive hardware. To start the counter, write a non-zero value. Reads will return 1 while the count is running and 0 when it has finished. Minimum count value is 4. Count values <4 will be treated as count value =4. Note that synchronisation to the register clock domain costs 2 register clock cycles and the counter cannot compensate for that.