Casio SK 8A - 9. SAMPLING CIRCUIT

9. SAMPLING CIRCUIT
VC
Fig. 1 Sample Sound Input Circuit
Start
Fig. 2 Vin Input Trigger Level
As shown in Fig. 1, the circuit provides sampling signals to the Vin terminal of the CPU. Resistors
lOOKohm and (100 + 4.7) Kohm bias the sampling signal on 2.863V.
When the sampling sound level exceeds ± 0.315V as shown in Fig. 2, the CPU starts to transmit
the sampling sound data to the RAMs during the following period.
While sampling, the CPU transmits the sampling sound data to the sampling RAMs directly.
While sampling, CPU does not output key common signals (KOO ~ K09) so that the keyboard
becomes inoperative.
Sampled sounds are digitized in CPU and transmitted to the RAM.