1. ATtiny2313 Fuse Programming CS-423 Dick Steflik

2. Whats a Fuse Fuses are used to hold important configuration information for the MPU Not really a fuse, just a few really important bytes of memory  1 means unprogrammed, 0 means programmed  unlike a fuse they can be reprogrammed  on the ATtiny2313 there are 3 fuse bytes low byte (lbyte)‏ high byte (hbyte)‏ extended byte (ebyte)‏

3. Low Byte 7 (0) – CKDIV8 – Divide Clock by 8 6 (1) – CKOUT – Output clock on CKOUT pin 5 (1) – SUT1 – Select start-up time 4 (0) – SUT0 – Select start-up time 3 (0) – CKSEL3 – Select clock source 2 (1) – CKSEL2 – Select clock source 1 (0) – CKSEL1 – Select clock source 0 (0) – CKSEL0 – Select clock source

4. Note: Default Low Byte Default Low Byte value is 0x64  Divide clock by 8  Internal RC Oscillator (8 MHz)‏  This means default speed is 1 MHz

5. Select Start-up time Default value (1 0) results in Maximum start-up time

6. Clocking Options- CKSEL 3..0 0000 – External Clock 0010 – Internal RC Oscillator (4 Mhz)‏ 0100 – Internal RC Oscillator (8 Mhz)‏ 0110 – Watchdog Oscillator (128 KHz)‏ 1000-1111 – External Chrystal/Ceramic Resonator 0001,0011,0101,0111 - Reserved

7. High Byte 7 (1) – DWEN – debugWIRE Enable 6 (1) – EESAVE – EEPROM is preserved during chip erase 5 (0) – SPIEN – SPI Enable 4 (1) – WDTON – Watchdog timer always on 3 (1) – BODLEVEL2 – brownout detector trig level 2 (1) – BODLEVEL1 – brownout detector trig level 1 (1) – BODLEVEL0 – brownout detector trig level 0 (1) – RSTDISBL – External Reset disable

8. Brownout Detection Trigger Level The ATtiny2313 has an On-chip Brown-out Detection circuit that monitors Vcc to fixed trigger levels Programmed by BODLEVEL 2..0 Fuses 1 1 1 BOD disabled 1 1 0 1.8 v 1 0 1 2.7 v 1 0 0 4.3 v

9. Extended Byte 7 (1) – not used 6 (1) – not used 5 (1) – not used 4 (1) – not used 3 (1) – not used 2 (1) – not used 1 (1) – not used 0 (1)– SELFPRGEN – Self programming Enable

10. Fuse Programming Can be done through the Studio GUI if you are using the Atmel programmer AVRDUDE & Parallel Port programmer  Use the -U option as follows: Avrdude -p Attiny2313 -c dapa -v -U lfuse:w:0xE4