ATMEGA325P-20AU Atmel, ATMEGA325P-20AU Datasheet - Page 204

• Manufacturer Part Number: ATMEGA325P-20AU
• Description: IC MCU AVR 32K FLASH 64-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA325P-20AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, UART, USI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 64TQFP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Rom Size: 1 KB
• Height: 1 mm
• Length: 14 mm
• Supply Voltage (max): 5.5 V, 5.8 V
• Supply Voltage (min): 2.4 V, 2.7 V
• Width: 14 mm
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1005 - ISP 4PORT FOR ATMEL AVR MCU JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPIATAVRISP2 - PROGRAMMER AVR IN SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA325P-16AU; ATMEGA325P-16AU

20.3
20.3.1
20.3.2
204
Register Description
ATmega325P/3250P
ADCSRB – ADC Control and Status Register B
ACSR – Analog Comparator Control and Status Register
Table 20-1.
• Bit 6 – ACME: Analog Comparator Multiplexer Enable
When this bit is written logic one and the ADC is switched off (ADEN in ADCSRA is zero), the
ADC multiplexer selects the negative input to the Analog Comparator. When this bit is written
logic zero, AIN1 is applied to the negative input of the Analog Comparator. For a detailed
description of this bit, see
• Bit 7 – ACD: Analog Comparator Disable
When this bit is written logic one, the power to the Analog Comparator is switched off. This bit
can be set at any time to turn off the Analog Comparator. This will reduce power consumption in
Active and Idle mode. When changing the ACD bit, the Analog Comparator Interrupt must be
disabled by clearing the ACIE bit in ACSR. Otherwise an interrupt can occur when the bit is
changed.
• Bit 6 – ACBG: Analog Comparator Bandgap Select
When this bit is set, a fixed bandgap reference voltage replaces the positive input to the Analog
Comparator. When this bit is cleared, AIN0 is applied to the positive input of the Analog Compar-
ator. When the bandgap reference is used as input to the analog comparator, it will take a
certain time for the voltage to stabilize. If not stabilized, the the first converison may give a wrong
value.
• Bit 5 – ACO: Analog Comparator Output
The output of the Analog Comparator is synchronized and then directly connected to ACO. The
synchronization introduces a delay of 1 - 2 clock cycles.
Bit
(0x7B)
Read/Write
Initial Value
Bit
0x30 (0x50)
Read/Write
Initial Value
ACME
1
1
1
1
1
1
1
See Section “10.3” on page 48.
Analog Comparator Multiplexed Input (Continued)
ACD
R/W
ADEN
7
0
R
7
–
0
0
0
0
0
0
0
0
ACBG
ACME
R/W
R/W
”Analog Comparator Multiplexed Input” on page
6
0
6
0
MUX2:0
001
010
011
100
101
110
111
ACO
N/A
R
5
R
5
–
0
Analog Comparator Negative Input
ADC1
ADC2
ADC3
ADC4
ADC5
ADC6
ADC7
R/W
ACI
4
0
R
4
–
0
ACIE
R/W
3
0
R
3
–
0
ADTS2
ACIC
R/W
R/W
2
0
2
0
ACIS1
ADTS1
R/W
R/W
1
0
1
0
203.
ACIS0
ADTS0
R/W
R/W
0
0
0
0
8023F–AVR–07/09
ADCSRB
ACSR