ATMEGA88-20MU Atmel, ATMEGA88-20MU Datasheet - Page 275

• Manufacturer Part Number: ATMEGA88-20MU
• Description: IC AVR MCU 8K 20MHZ 5V 32-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA88-20MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K 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: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Package: 32MLF EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 23
• Interface Type: SPI/TWI/USART
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• Processor Series: ATMEGA8x
• Core: AVR8
• Data Ram Size: 1 KB
• Maximum Clock Frequency: 20 MHz
• 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, ATAVRTS2080A, ATASTK512-EK1-IND
• Minimum Operating Temperature: - 40 C
• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 20 MIPS
• Eeprom Memory: 512 Bytes
• Input Output: 23
• Interface: SPI/TWI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 32-pin MLF
• Programmable Memory: 8K Bytes
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 4.5-5.5 V
• Controller Family/series: AVR MEGA
• No. Of I/o's: 23
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 1KB
• No. Of Timers: 3
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.8.1
26.8.2
26.8.3
26.8.4
26.8.5
26.8.6
2545S–AVR–07/10
Performing Page Erase by SPM
Filling the Temporary Buffer (Page Loading)
Performing a Page Write
Using the SPM Interrupt
Consideration While Updating BLS
Prevent Reading the RWW Section During Self-Programming
To execute Page Erase, set up the address in the Z-pointer, write “X0000011” to SPMCSR and
execute SPM within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored.
The page address must be written to PCPAGE in the Z-register. Other bits in the Z-pointer will
be ignored during this operation.
• Page Erase to the RWW section: The NRWW section can be read during the Page Erase.
• Page Erase to the NRWW section: The CPU is halted during the operation.
To write an instruction word, set up the address in the Z-pointer and data in R1:R0, write
“00000001” to SPMCSR and execute SPM within four clock cycles after writing SPMCSR. The
content of PCWORD in the Z-register is used to address the data in the temporary buffer. The
temporary buffer will auto-erase after a Page Write operation or by writing the RWWSRE bit in
SPMCSR. It is also erased after a system reset. Note that it is not possible to write more than
one time to each address without erasing the temporary buffer.
If the EEPROM is written in the middle of an SPM Page Load operation, all data loaded will be
lost.
To execute Page Write, set up the address in the Z-pointer, write “X0000101” to SPMCSR and
execute SPM within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored.
The page address must be written to PCPAGE. Other bits in the Z-pointer must be written to
zero during this operation.
• Page Write to the RWW section: The NRWW section can be read during the Page Write.
• Page Write to the NRWW section: The CPU is halted during the operation.
If the SPM interrupt is enabled, the SPM interrupt will generate a constant interrupt when the
SELFPRGEN bit in SPMCSR is cleared. This means that the interrupt can be used instead of
polling the SPMCSR Register in software. When using the SPM interrupt, the Interrupt Vectors
should be moved to the BLS section to avoid that an interrupt is accessing the RWW section
when it is blocked for reading. How to move the interrupts is described in
55.
Special care must be taken if the user allows the Boot Loader section to be updated by leaving
Boot Lock bit11 unprogrammed. An accidental write to the Boot Loader itself can corrupt the
entire Boot Loader, and further software updates might be impossible. If it is not necessary to
change the Boot Loader software itself, it is recommended to program the Boot Lock bit11 to
protect the Boot Loader software from any internal software changes.
During Self-Programming (either Page Erase or Page Write), the RWW section is always
blocked for reading. The user software itself must prevent that this section is addressed during
the self programming operation. The RWWSB in the SPMCSR will be set as long as the RWW
section is busy. During Self-Programming the Interrupt Vector table should be moved to the BLS
as described in
the RWW section after the programming is completed, the user software must clear the
“Interrupts” on page
55, or the interrupts must be disabled. Before addressing
ATmega48/88/168
“Interrupts” on page
275