st2024c Sitronix Technology Corporation, st2024c Datasheet - Page 37

• Manufacturer Part Number: st2024c
• Description: 24k 8-bit Single Chip Microcontroller
• Manufacturer: Sitronix Technology Corporation

14.3.3 Two-Pin Push Pull mode (Accurate to 8 bits)
Two-Pin Push Pull mode is designed for buzzer. It requires
two pins that PB0 and PB1. When the DAC value is 0, both
pins are low. When the DAC value is positive, PB1 goes high
with a duty cycle proportional to the output value, while PB0
stays low. When the DAC value is negative, PB0 goes high
with a duty cycle proportional to the output value, while PB1
stays low. This mode offers a resolution of 8 bits.
Ver 2.2
PB0
PB0
PB1
PB1
High
High
High
High
Low
Low
Low
Low
Where X=0 to -128
Where X=0 to 127
|X|
DAC = X
DAC = X
X
FIGURE 14-20:
FIGURE 14-21: Two-Pin Push Pull Application Circuit
128+X
128-X
ST2024C
Two-Pin Push Pull PWM DAC Wave-form
32
P B0
PB1
DAC = -48
DAC = 32
48
96
80
37/54
Figure 13-19 shows examples of DAC output waveforms
with different output values. Each pulse of the DAC is divided
into 128 segments per sample period. For a positive output
value x=0 to 127, PB1 goes high for X segments while PB0
stays low. For a negative output value x=0 to -127, PB0 goes
high for |X| segments while PB1 stays low.
DAC = 96
DAC = 0
96
Buzzer
32
DAC = 127
DAC = -128
127
ST2024C
1
1/31/08