Datasheet

28.8.14. Reading the Calibration Byte
The algorithm for reading the Calibration byte is as follows (Please refer to Programming the Flash for
details on Command and Address loading):
1. Step A: Load Command “0000 1000”.
2. Step B: Load Address Low Byte, 0x00.
3. Set OE to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.
4. Set OE to “1”.
28.8.15. Parallel Programming Characteristics
For characteristics of the Parallel Programming, please refer to Parallel Programming Characteristics.
28.9. Serial Downloading
Both the Flash and EEPROM memory arrays can be programmed using the serial SPI bus while RESET
is pulled to GND. The serial interface consists of pins SCK, MOSI (input) and MISO (output). After
RESET is set low, the Programming Enable instruction needs to be executed first before program/erase
operations can be executed.
Figure 28-6. Serial Programming and Verify
VCC
GND
EXTCLK
SCK
MISO
MOSI
RESET
+1.8 - 5.5V
AVCC
+1.8 - 5.5V
(2)
Note:
1. If the device is clocked by the internal Oscillator, it is no need to connect a clock source to the
XTAL1 pin.
2. V
CC
- 0.3V < AVCC < V
CC
+ 0.3V, however, AVCC should always be within 1.8 - 5.5V
When programming the EEPROM, an auto-erase cycle is built into the self-timed programming operation
(in the Serial mode ONLY) and there is no need to first execute the Chip Erase instruction. The Chip
Erase operation turns the content of every memory location in both the Program and EEPROM arrays
into 0xFF.
Depending on CKSEL Fuses, a valid clock must be present. The minimum low and high periods for the
serial clock (SCK) input are defined as follows:
• Low: > 2 CPU clock cycles for f
ck
< 12MHz, 3 CPU clock cycles for f
ck
≥ 12MHz
• High: > 2 CPU clock cycles for f
ck
< 12MHz, 3 CPU clock cycles for f
ck
≥ 12MHz
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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