UPD780973 Datasheet, PDF (212/301 Pages) NEC – 8-Bit Single-Chip Microcontrollers

CHAPTER 17 SOUND GENERATOR
17.4 Sound Generator Operations
17.4.1 To output basic cycle signal SGOF (without amplitude)
Select SGOF output by setting bit 3 (SGOB) of the sound generator control register (SGCR) to “0”.
The basic cycle signal with a frequency specified by the SGCL0 to SGCL2 and SGBR0 to SGBR3 is output.
At the same time, the amplitude signal with an amplitude specified by the SGAM0 to SGAM6 is output from the
SGOA pin.
Figure 17-6. Sound Generator Output Operation Timing
Timer
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Comparator 1 coincidence
SGOF
SGOA
17.4.2 To output basic cycle signal SGO (with amplitude)
Select SGO output by setting bit 3 (SGOB) of the sound generator control register (SGCR) to “1”.
The basic cycle signal with a frequency specified by the SGCL0 to SGCL2 and SGBR0 to SGBR3 is output.
When SGO output is selected, the SGOA pin can be used as a PCL output (clock output) or I/O port pin.
Figure 17-7. Sound Generator Output Operation Timing
Timer
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Comparator 1 coincidence
SGOF
SGOA
SGO
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