ATMEGA16-16AQ Atmel, ATMEGA16-16AQ Datasheet - Page 20

MCU AVR 16K FLASH 16MHZ 44-TQFP

ATMEGA16-16AQ

Manufacturer Part Number
ATMEGA16-16AQ
Description
MCU AVR 16K FLASH 16MHZ 44-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet

Specifications of ATMEGA16-16AQ

Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
16KB (8K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
44-TQFP, 44-VQFP
For Use With
ATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK500 - PROGRAMMER AVR STARTER KIT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA16-16AQ
Manufacturer:
Atmel
Quantity:
10 000
Part Number:
ATMEGA16-16AQR
Manufacturer:
Atmel
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2466T–AVR–07/10
• Bit 1 – EEWE: EEPROM Write Enable
The EEPROM Write Enable Signal EEWE is the write strobe to the EEPROM. When address
and data are correctly set up, the EEWE bit must be written to one to write the value into the
EEPROM. The EEMWE bit must be written to one before a logical one is written to EEWE, oth-
erwise no EEPROM write takes place. The following procedure should be followed when writing
the EEPROM (the order of steps 3 and 4 is not essential):
The EEPROM can not be programmed during a CPU write to the Flash memory. The software
must check that the Flash programming is completed before initiating a new EEPROM write.
Step 2 is only relevant if the software contains a Boot Loader allowing the CPU to program the
Flash. If the Flash is never being updated by the CPU, step 2 can be omitted. See
Support – Read-While-Write Self-Programming” on page 246
programming.
Caution: An interrupt between step 5 and step 6 will make the write cycle fail, since the
EEPROM Master Write Enable will time-out. If an interrupt routine accessing the EEPROM is
interrupting another EEPROM Access, the EEAR or EEDR reGister will be modified, causing the
interrupted EEPROM Access to fail. It is recommended to have the Global Interrupt Flag cleared
during all the steps to avoid these problems.
When the write access time has elapsed, the EEWE bit is cleared by hardware. The user soft-
ware can poll this bit and wait for a zero before writing the next byte. When EEWE has been set,
the CPU is halted for two cycles before the next instruction is executed.
• Bit 0 – EERE: EEPROM Read Enable
The EEPROM Read Enable Signal – EERE – is the read strobe to the EEPROM. When the cor-
rect address is set up in the EEAR Register, the EERE bit must be written to a logic one to
trigger the EEPROM read. The EEPROM read access takes one instruction, and the requested
data is available immediately. When the EEPROM is read, the CPU is halted for four cycles
before the next instruction is executed.
The user should poll the EEWE bit before starting the read operation. If a write operation is in
progress, it is neither possible to read the EEPROM, nor to change the EEAR Register.
The calibrated Oscillator is used to time the EEPROM accesses.
gramming time for EEPROM access from the CPU.
Table 1. EEPROM Programming Time
Note:
The following code examples show one assembly and one C function for writing to the
EEPROM. The examples assume that interrupts are controlled (for example by disabling inter-
rupts globally) so that no interrupts will occur during execution of these functions. The examples
EEPROM write (from CPU)
1. Wait until EEWE becomes zero.
2. Wait until SPMEN in SPMCR becomes zero.
3. Write new EEPROM address to EEAR (optional).
4. Write new EEPROM data to EEDR (optional).
5. Write a logical one to the EEMWE bit while writing a zero to EEWE in EECR.
6. Within four clock cycles after setting EEMWE, write a logical one to EEWE.
1. Uses 1 MHz clock, independent of CKSEL Fuse setting.
Symbol
Number of Calibrated RC
Oscillator Cycles
8448
(1)
Typ Programming Time
Table 1
ATmega16(L)
for details about boot
8.5 ms
lists the typical pro-
“Boot Loader
20

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