AT90PWM2B Atmel Corporation, AT90PWM2B Datasheet - Page 30

• 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

7.1.5
7.2
30
Clock Sources
AT90PWM2/3/2B/3B
ADC Clock – clk
The ADC is provided with a dedicated clock domain. This allows halting the CPU and I/O clocks
in order to reduce noise generated by digital circuitry. This gives more accurate ADC conversion
results.
The device has the following clock source options, selectable by Flash Fuse bits as illustrated
Table 7-1. The clock from the selected source is input to the AVR clock generator, and routed to
the appropriate modules.
Table 7-1.
Note:
Table 7-2.
The various choices for each clocking option is given in the following sections. When the CPU
wakes up from Power-down or Power-save, the selected clock source is used to time the start-
ADC
Device Clocking Option
External Crystal/Ceramic Resonator
Reserved
PLL output divided by 4 : 16 MHz
Calibrated Internal RC Oscillator
Reserved
External Clock
Device Clocking Option
External Crystal/Ceramic Resonator
PLL output divided by 4 : 16 MHz / External
Crystal/Ceramic Resonator/ PLL driven by External Crystal
/Ceramic Resonator
PLL output divided by 4 : 16 MHz / PLL driven by External
Crystal/Ceramic Resonator
Reserved
PLL output divided by 4 : 16 MHz
Calibrated Internal RC Oscillator
PLL output divided by 4 : 16 MHz / PLL driven by External
clock
External Clock
1.For all fuses “1” means unprogrammed while “0” means programmed
2.Ext Osc : External Osc
3.RC Osc : Internal RC Oscillator
4.Ext Clk : External Clock Input
1. For all fuses “1” means unprogrammed while “0” means programmed.
Device Clocking Options Select
Device Clocking Options Select AT90PWM2B/3B
(1)
AT90PWM2/3
System
Clock
Ext Osc
Ext Osc
PLL / 4
N/A
PLL / 4
RC Osc
PLL / 4
Ext Clk
(2)
PLL Input
RC Osc
Ext Osc
Ext Osc
N/A
RC Osc
RC Osc
Ext Clk
RC Osc
(4)
(3)
1111 - 1000
0111- 0100
CKSEL3..0
0011
0010
0001
0000
1111 - 1000
0111- 0110
4317J–AVR–08/10
CKSEL3..0
0100
0101
0011
0010
0001
0000
(1)