ATMEGA324P-A15MZ Atmel, ATMEGA324P-A15MZ Datasheet - Page 30

• Manufacturer Part Number: ATMEGA324P-A15MZ
• Description: MCU AVR 32KB FLASH 15MHZ 44-VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA324P-A15MZ

• Package / Case: 44-VQFN Exposed Pad
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Number Of I /o: 32
• Eeprom Size: 1K x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 2K x 8
• Program Memory Size: 32KB (32K 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

Oscillator Calibration
Register – OSCCAL
30
ATmega32(L)
When this Oscillator is selected, start-up times are determined by the SUT fuses as shown in
Table
Table 10. Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
Note:
• Bits 7..0 – CAL7..0: Oscillator Calibration Value
Writing the calibration byte to this address will trim the Internal Oscillator to remove process vari-
ations from the Oscillator frequency. During Reset, the 1 MHz calibration value which is located
in the signature row High Byte (address 0x00) is automatically loaded into the OSCCAL Regis-
ter. If the internal RC is used at other frequencies, the calibration values must be loaded
manually. This can be done by first reading the signature row by a programmer, and then store
the calibration values in the Flash or EEPROM. Then the value can be read by software and
loaded into the OSCCAL Register. When OSCCAL is zero, the lowest available frequency is
chosen. Writing non-zero values to this register will increase the frequency of the Internal Oscil-
lator. Writing $FF to the register gives the highest available frequency. The calibrated Oscillator
is used to time EEPROM and Flash access. If EEPROM or Flash is written, do not calibrate to
more than 10% above the nominal frequency. Otherwise, the EEPROM or Flash write may fail.
Note that the Oscillator is intended for calibration to 1.0, 2.0, 4.0, or 8.0 MHz. Tuning to other
values is not guaranteed, as indicated in
Table 11. Internal RC Oscillator Frequency Range.
Bit
Read/Write
Initial Value
OSCCAL Value
SUT1..0
10
00
01
11
10. XTAL1 and XTAL2 should be left unconnected (NC).
(1)
$00
$7F
$FF
1. The device is shipped with this option selected.
CAL7
R/W
Start-up Time from
7
Power-down and
Power-save
Min Frequency in Percentage of
6 CK
6 CK
6 CK
CAL6
R/W
Nominal Frequency (%)
6
CAL5
R/W
5
100
Device Specific Calibration Value
50
75
CAL4
R/W
Additional Delay
4
Table
(V
from Reset
CC
4.1 ms
65 ms
Reserved
= 5.0V)
CAL3
11.
–
R/W
3
Max Frequency in Percentage of
CAL2
R/W
2
Nominal Frequency (%)
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
CAL1
R/W
1
100
150
200
CAL0
R/W
0
OSCCAL
2503N–AVR–06/08