ATtiny25 Automotive Atmel Corporation, ATtiny25 Automotive Datasheet - Page 134

• Manufacturer Part Number: ATtiny25 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny25 Automotive

• Flash (kbytes): 2 Kbytes
• Pin Count: 8
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 6
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 5
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

20.4.5
21. Memory Programming
21.1
134
Program And Data Memory Lock Bits
ATtiny25/45/85
Programming Time for Flash when Using SPM
Flash corruption can easily be avoided by following these design recommendations (one is
sufficient):
The calibrated RC Oscillator is used to time Flash accesses.
gramming time for Flash accesses from the CPU.
Table 20-1.
This section describes the different methods for Programming the ATtiny25/45/85 memories.
The ATtiny25/45/85 provides two Lock bits which can be left unprogrammed (“1”) or can be pro-
grammed (“0”) to obtain the additional security listed in
erased to “1” with the Chip Erase command.
Program memory can be read out via the debugWIRE interface when the DWEN fuse is pro-
grammed, even if the Lock Bits are set. Thus, when Lock Bit security is required, should always
debugWIRE be disabled by clearing the DWEN fuse.
Table 21-1.
Note:
Flash write (Page Erase, Page Write, and
write Lock bits by SPM)
LB2
LB1
1. Keep the AVR RESET active (low) during periods of insufficient power supply voltage.
2. Keep the AVR core in Power-down sleep mode during periods of low V
This can be done by enabling the internal Brown-out Detector (BOD) if the operating
voltage matches the detection level. If not, an external low V
can be used. If a reset occurs while a write operation is in progress, the write operation
will be completed provided that the power supply voltage is sufficient.
vent the CPU from attempting to decode and execute instructions, effectively protecting
the SPMCSR Register and thus the Flash from unintentional writes.
Lock Bit Byte
1. “1” means unprogrammed, “0” means programmed
SPM Programming Time
Lock Bit Byte
Symbol
()
Bit No
7
6
5
4
3
2
1
0
Description
–
–
–
–
–
–
Lock bit
Lock bit
Min Programming Time
3.7 ms
Table
Table 20-1
21-2. The Lock bits can only be
Default Value
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
CC
reset protection circuit
Max Programming Time
shows the typical pro-
CC
. This will pre-
4.5 ms
7598H–AVR–07/09