AT90PWM1 Atmel Corporation, AT90PWM1 Datasheet - Page 36

• Manufacturer Part Number: AT90PWM1
• Manufacturer: Atmel Corporation

Specifications of AT90PWM1

• 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
• 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
• 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

36
AT90PWM1
• Bits 3..0 – CLKPS3..0: Clock Prescaler Select Bits 3 - 0
These bits define the division factor between the selected clock source and the internal system
clock. These bits can be written run-time to vary the clock frequency to suit the application
requirements. As the divider divides the master clock input to the MCU, the speed of all synchro-
nous peripherals is reduced when a division factor is used. The division factors are given in
Table
The CKDIV8 Fuse determines the initial value of the CLKPS bits. If CKDIV8 is unprogrammed,
the CLKPS bits will be reset to “0000”. If CKDIV8 is programmed, CLKPS bits are reset to
“0011”, giving a division factor of 8 at start up. This feature should be used if the selected clock
source has a higher frequency than the maximum frequency of the device at the present operat-
ing conditions. Note that any value can be written to the CLKPS bits regardless of the CKDIV8
Fuse setting. The Application software must ensure that a sufficient division factor is chosen if
the selcted clock source has a higher frequency than the maximum frequency of the device at
the present operating conditions. The device is shipped with the CKDIV8 Fuse programmed.
Table 7-11.
CLKPS3
7-11.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Clock Prescaler Select
CLKPS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
CLKPS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
CLKPS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Clock Division Factor
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
128
256
16
32
64
1
2
4
8
4378C–AVR–09/08