ATmega32C1 Automotive Atmel Corporation, ATmega32C1 Automotive Datasheet - Page 236

• 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

18.5.1
18.5.2
236
Atmel ATmega16/32/64/M1/C1
ADC Input Channels
ADC Voltage Reference
If Auto Triggering is used, the exact time of the triggering event can be indeterministic. Special
care must be taken when updating the ADMUX Register, in order to control which conversion
will be affected by the new settings.
If both ADATE and ADEN is written to one, an interrupt event can occur at any time. If the
ADMUX Register is changed in this period, the user cannot tell if the next conversion is based
on the old or the new settings. ADMUX can be safely updated in the following ways:
When updating ADMUX in one of these conditions, the new settings will affect the next ADC
conversion.
When changing channel selections, the user should observe the following guidelines to ensure
that the correct channel is selected:
Note:
The reference voltage for the ADC (V
ended channels that exceed V
either AV
AV
erated from the internal bandgap reference (V
the external AREF pin is directly connected to the ADC, and the reference voltage can be
made more immune to noise by connecting a capacitor between the AREF pin and ground.
V
a high impedant source, and only a capacitive load should be connected in a system.
REF
1. When ADATE or ADEN is cleared.
2. During conversion, with taking care of the trigger source event, when it is possible.
3. After a conversion, before the interrupt flag used as trigger source is cleared.
• In Single Conversion mode, always select the channel before starting the conversion. The
• In Free Running mode, always select the channel before starting the first conversion. The
• In Free Running mode, because the amplifier clear the ADSC bit at the end of an amplified
CC
channel selection may be changed one ADC clock cycle after writing one to ADSC.
However, the simplest method is to wait for the conversion to complete before changing the
channel selection.
channel selection may be changed one ADC clock cycle after writing one to ADSC.
However, the simplest method is to wait for the first conversion to complete, and then
change the channel selection. Since the next conversion has already started automatically,
the next result will reflect the previous channel selection. Subsequent conversions will
reflect the new channel selection.
conversion, it is not possible to use the free running mode, unless ADSC bit is set again by
soft at the end of each conversion.
can also be measured at the AREF pin with a high impedant voltmeter. Note that V
is connected to the ADC through a passive switch. The internal 2.56V reference is gen-
When The ADC and COMPARATOR share the same channel (Possible configuration for
AMP1+, AMP1- and AMP2-), up to revision B of ATmega32M1 the comparator is disconnected
during the sampling of the ADC. For ATmega16/64 and ATmega32 revision C, the COMPARA-
TOR is always connected.
CC
, internal 2.56V reference, or external AREF pin.
REF
will result in codes close to 0x3FF. V
REF
) indicates the conversion range for the ADC. Single
BG
) through an internal amplifier. In either case,
REF
can be selected as
7647G–AVR–09/11
REF
is