SN8F2280 Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
8.4.5 TCn CLOCK FREQUENCY OUTPUT (BUZZER)
Buzzer output (TCnOUT) is from TCn timer/counter frequency output function. If setting the TC0 clock frequency, the
clock signal is output to P5.3 and the P5.3 general purpose I/O function is auto-disable. The TCnOUT frequency is
divided by 2 from TCn interval time. TCnOUT frequency is 1/2 TCn frequency. The TCn clock has many combinations
and easily to make difference frequency. The TCnOUT frequency waveform is as following.
¾
Example: Setup TC0OUT output from TC0 to TC0OUT (P5.3). The external high-speed clock is 4MHz. The
TC0OUT frequency is 0.5KHz. Because the TC0OUT signal is divided by 2, set the TC0 clock to 1KHz. The
TC0 clock source is from external oscillator clock. T0C rate is Fcpu/4. The TC0RATE2~TC0RATE1 = 110.
TC0C = TCnR = 131.
MOV
B0MOV
A,#01100000B
TC0M,A
; Set the TC0 rate to Fcpu/4
MOV
B0MOV
B0MOV
A,#131
TC0C,A
TC0R,A
; Set the auto-reload reference value
B0BSET
B0BSET
B0BSET
FTC0OUT
FALOAD0
FTC0ENB
; Enable TC0 output to P5.3 and disable P5.3 I/O function
; Enable TC0 auto-reload function
; Enable TC0 timer
Note: Buzzer output is enable, and “PWM0OUT” must be “0”.
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