ATmega32C1 Automotive Atmel Corporation, ATmega32C1 Automotive Datasheet - Page 275

• Manufacturer Part Number: ATmega32C1 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATmega32C1 Automotive

• Flash (kbytes): 32 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 27
• Ext Interrupts: 27
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 1
• Can: 1
• Lin: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 125
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 1
• Dac Resolution (bits): 10
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 150
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

22. Analog Feature Considerations
22.1
22.2
22.3
7647G–AVR–09/11
Use of an Amplifier as Comparator Input
Use of an Amplifier as Comparator Input and ADC Input
Purpose
The ATmega16/32/64/M1/C1 features several analog features such as ADC, DAC, Amplifiers,
Comparators...
The purpose of this section is to describe the interaction between these features. This section
explains how to set the specific registers to get the system running.
Particularly the different peripheral clocks can interfere together, so special care has to be
considered.
The internal amplifiers provide differential amplification for ADC converter. To allow signed
result with the ADC, the output level of the amplifiers is shifted up with a Vref/2 voltage.
For this reason, when used with a comparator, a Vref/2 voltage is added to the voltage of the
amplifier outputs.
Figure 22-1. Amplifier and Comparator
The amplifier Clock comes from the ADC and is equal to the ADC Clock divided by 8.
The amplifier can be used as ADC input while it is used as comparator input. In that case,
each time the amplifier is selected as ADC input, the sampling and hold circuit of the ADC
loads the amplifier output. It results a decrease of the amplifier output voltage which can tog-
gle the comparator output.
ACMPx
AMPx+
AMPx-
AMPCMPx
Amplifier
Clock
+
-
AMPx
Atmel ATmega16/32/64/M1/C1
Analog Comparator
Negative Input
Comparator
Clock
+
-
ACxEN
Analog Comparator
Output
275