ATTINY461-20PU Atmel, ATTINY461-20PU Datasheet - Page 19

• Manufacturer Part Number: ATTINY461-20PU
• Description: Microcontrollers (MCU) 4kB Flash 0.256kB EEPROM 16 I/O Pins
• Manufacturer: Atmel

Specifications of ATTINY461-20PU

• Processor Series: ATTINY4x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: 2-Wire/SPI/USI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 2
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 11-ch x 10-bit
• Program Memory Type: Flash
• Program Memory Size: 4 KB
• Package / Case: PDIP-20
• Package: 20PDIP
• Device Core: AVR
• Family Name: ATtiny
• Maximum Speed: 20 MHz
• Ram Size: 256 Byte
• Operating Temperature: -40 to 85 °C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.3.7
2588E–AVR–08/10
Preventing EEPROM Corruption
The next code examples show assembly and C functions for reading the EEPROM. The exam-
ples assume that interrupts are controlled so that no interrupts will occur during execution of
these functions.
Note:
During periods of low V
too low for the CPU and the EEPROM to operate properly. These issues are the same as for
board level systems using EEPROM, and the same design solutions should be applied.
An EEPROM data corruption can be caused by two situations when the voltage is too low. First,
a regular write sequence to the EEPROM requires a minimum voltage to operate correctly. Sec-
ondly, the CPU itself can execute instructions incorrectly, if the supply voltage is too low.
EEPROM data corruption can easily be avoided by following this design recommendation:
Keep the AVR RESET active (low) during periods of insufficient power supply voltage. This can
be done by enabling the internal Brown-out Detector (BOD). If the detection level of the internal
BOD does not match the needed detection level, an external low V
Assembly Code Example
C Code Example
EEPROM_read:
unsigned char EEPROM_read(unsigned char ucAddress)
{
}
; Wait for completion of previous write
sbic EECR,EEPE
rjmp EEPROM_read
; Set up address (r18:r17) in address register
out EEARH, r18
out EEARL, r17
; Start eeprom read by writing EERE
sbi EECR,EERE
; Read data from data register
in
ret
/* Wait for completion of previous write */
while(EECR & (1<<EEPE))
/* Set up address register */
EEAR = ucAddress;
/* Start eeprom read by writing EERE */
EECR |= (1<<EERE);
/* Return data from data register */
return EEDR;
See
;
“Code Examples” on page
r16,EEDR
CC
, the EEPROM data can be corrupted because the supply voltage is
6.
CC
reset protection circuit can
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