ATMEGA164A-MCHR Atmel, ATMEGA164A-MCHR Datasheet - Page 38

• Manufacturer Part Number: ATMEGA164A-MCHR
• Description: IC MCU AVR 16K 20MHZ 44QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA164A-MCHR

• Package / Case: 44-VQFN Exposed Pad
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Speed: 20MHz
• Number Of I /o: 32
• Eeprom Size: 512 x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Program Memory Size: 16KB (16K x 8)
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Connectivity: I²C, SPI, UART/USART
• Core Size: 8-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.7
8.8
8272A–AVR–01/10
128 kHz Internal Oscillator
External Clock
The 128 kHz internal Oscillator is a low power Oscillator providing a clock of 128 kHz. The fre-
quency is nominal at 3V and 25°C. This clock may be select as the system clock by
programming the CKSEL Fuses to “0011” as shown in
Table 8-12.
Note:
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 8-13.
To drive the device from an external clock source, XTAL1 should be driven as shown in
8-4. To run the device on an external clock, the CKSEL Fuses must be programmed to “0000”.
Figure 8-4.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
164A/164PA/324A/324PA/644A/644PA/1284/1284P
BOD enabled
Fast rising power
Slowly rising power
Power Conditions
8-13.
8-15.
1. Note that the 128kHz oscillator is a very low power clock source, and is not designed for high
accuracy.
128 kHz Internal Oscillator Operating Modes
Start-up Times for the 128 kHz Internal Oscillator
External Clock Drive Configuration
Nominal Frequency
EXTERNAL
128 kHz
SIGNAL
CLOCK
Start-up Time from Power-
down and Power-save
NC
Reserved
6 CK
6 CK
6 CK
XTAL2
XTAL1
GND
Table
(2)
Additional Delay from
8-12.
14CK + 64 ms
14CK + 4 ms
Reset
14CK
CKSEL3..0
0011
SUT1..0
00
01
10
11
Figure
38