uPD789074 Subseries 8-Bit Single-Chip Microcontrollers UD - Home

CHAPTER 6 16-BIT TIMER 906.4.5 Buzzer output operationThe buzzer frequency is set using buzzer output control register 90 (BZC90) based on the count clock selectedwith TCL901 and TCL900 of TMC90 (source clock). A square wave of the set buzzer frequency is output.Table 6-4 shows the buzzer frequency.To operate 16-bit timer 90 as a buzzer output, the following settings are required.• Set P31 to output mode (PM31 = 0).• Reset output latch of P31 to 0.• Set a count clock by using TCL901 and TCL900.• Set BZC90 as shown in Figure 6-12.Figure 6-12. Settings of Buzzer Output Control Register 90 for Buzzer Output OperationBCS902 BCS901 BCS900 BZOE90BZC900 0 0 0 0/1 0/1 0/1 1Enables buzzer outputSetting of buzzer frequency (see Table 6-4)Table 6-4. Buzzer Frequency of 16-Bit Timer 90BCS902 BCS901 BCS900Buzzer FrequencyfX =10.0 MHz Operation NotefX = 5.0 MHz Operationfcl = fX/2 2 fcl = fX/2 6 fcl = fX/2 4 fcl = fX/2 2 fcl = fX/2 6 fcl = fX/2 40 0 0 fcl/2 4 156 kHz 9.77 kHz 39.1 kHz 78.1 kHz 4.88 kHz 19.5 kHz0 0 1 fcl/2 5 78.1 kHz 4.88 kHz 19.5 kHz 39.1 kHz 2.44 kHz 9.77 kHz0 1 0 fcl/2 8 9.77 kHz 610 Hz 2.44 kHz 4.88 kHz 305 Hz 1.22 kHz0 1 1 fcl/2 9 4.88 kHz 305 Hz 1.22 kHz 2.44 kHz 153 Hz 610 Hz1 0 0 fcl/2 10 2.44 kHz 153 Hz 610 Hz 1.22 kHz 76.3 Hz 305 Hz1 0 1 fcl/2 11 1.22 kHz 76.3 Hz 305 Hz 610 Hz 38.1 Hz 153 Hz1 1 0 fcl/2 12 610 Hz 38.1 Hz 153 Hz 305 Hz 19.1 Hz 76.3 Hz1 1 1 fcl/2 13 305 Hz 19.1 Hz 76.3 Hz 153 Hz 9.54 Hz 38.1 HzNote Expanded-specification products only.RemarkfX: System clock oscillation frequency94User’s Manual U14801EJ3V1UD