AT90PWM1 Atmel Corporation, AT90PWM1 Datasheet - Page 186

• 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

19.5
186
Changing Channel or Reference Selection
AT90PWM1
Figure 19-6. ADC Timing Diagram, Auto Triggered Conversion
Figure 19-7. ADC Timing Diagram, Free Running Conversion
Table 60. ADC Conversion Time
The MUXn and REFS1:0 bits in the ADMUX Register are single buffered through a temporary
register to which the CPU has random access. This ensures that the channels and reference
selection only takes place at a safe point during the conversion. The channel and reference
selection is continuously updated until a conversion is started. Once the conversion starts, the
channel and reference selection is locked to ensure a sufficient sampling time for the ADC. Con-
tinuous updating resumes in the last ADC clock cycle before the conversion completes (ADIF in
ADCSRA is set). Note that the conversion starts on the following rising ADC clock edge after
ADSC is written. The user is thus advised not to write new channel or reference selection values
to ADMUX until one ADC clock cycle after ADSC is written.
Condition
Sample & Hold
(Cycles from Start of Conversion)
Conversion Time
(Cycles)
Cycle Number
ADC Clock
Trigger
Source
ADATE
ADIF
ADCH
ADCL
Prescaler
Reset
MUX and REFS
Update
1
2
3
Sample &
Hold
4
First Conversion
5
6
13.5
7
25
One Conversion
8
Cycle Number
ADC Clock
ADSC
ADIF
ADCH
ADCL
Conversion
13
Conversion
Complete
Complete
One Conversion
14
14
Single Ended
Conversion,
15
15
Normal
15.5
16
16
3.5
Next Conversion
1
Sign and MSB of Result
Sign and MSB of Result
LSB of Result
LSB of Result
2
MUX and REFS
Update
Next Conversion
1
Prescaler
Reset
3
Sample & Hold
2
4
Auto Triggered
Conversion
4378C–AVR–09/08
16
2