AT90PWM2B Atmel Corporation, AT90PWM2B Datasheet - Page 141

• Manufacturer Part Number: AT90PWM2B
• Manufacturer: Atmel Corporation

Specifications of AT90PWM2B

• Flash (kbytes): 8 Kbytes
• Pin Count: 24
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 19
• Ext Interrupts: 4
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 125
• Analog Comparators: 2
• Resistive Touch Screen: No
• Dac Channels: 1
• Dac Resolution (bits): 10
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 105
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 1
• Pwm Channels: 7
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

16.7.1
4317J–AVR–08/10
Frequency distribution
The frequency modulation is done by switching two frequencies in a 16 consecutive cycle frame.
These two frequencies are f
frequency and f
in the frame is (d-16) and the number of f
uted in the frame according to a predefined pattern. This pattern can be as given in the following
table or by any other implementation which give an equivallent evenly distribution.
Table 16-5.
While ‘X’ in the table, f
So for each row, a number of fb2 take place of fb1.
Figure 16-12. Resulting Frequency versus d.
Distribution of fb2 in the modulated frame
Fraction
al
Divider
(d)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
d:
f
b1
0
PWM - cycle
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1
Distribution of f
b2
2
1
X
X
X
X
X
X
X
is the nearest base frequency below the wanted frequency. The number of f
3
2
X
X
X
X
X
X
X
X
X
X
X
b2
4
prime to f
3
X
X
X
b1
b2
5
and f
in the modulated frame
4
X
X
X
X
X
X
X
X
X
X
X
X
X
6
b1
b2
in cycle corresponding cycle.
7
where f
5
X
X
X
X
X
8
b2
6
X
X
X
X
X
X
X
X
X
is d. The f
b1
9 10 11 12 13 14 15
is the nearest base frequency above the wanted
7
X
8
X
X
X
X
X
X
X
X
X
X
X
X
X
X
b1
and f
AT90PWM2/3/2B/3B
9
X
X
X
X
X
X
b2
frequencies are evenly distrib-
10
X
X
X
X
X
X
X
X
X
X
11
X
X
f
12
X
X
X
X
X
X
X
X
X
X
X
X
b2
13
X
X
X
X
f
OP
14
X
X
X
X
X
X
X
X
15
141
b1