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Table of Contents
Dev board 1
Program fuses using AtmelStudio and Olimex AVR-ISP500 - STK500 programmer.
The Olimex AVR-ISP500 has an external clock output on ICSP10 pin 3 for rescuing AVRs with enabled external clock fuse but no external clock This clock output can be really helpful when target AVR is accidentally programmed with External Clock FUSE option. To resurrect it just wire ICSP10 pin 3 to XTAL1 pin of the target AVR chip and initiate a programming session to fix the FUSE values.
Power from external battery.
| Setting | Default | Set |
|---|---|---|
| BODLEVEL | Disabled | Disabled |
| RSTDISBL | Clr | Clr |
| DWEN | Clr | Clr |
| SPIEN | Set | Set |
| WDTON | Clr | Clr |
| EESAVE | Clr | Clr |
| BOOTSZ | 2048W_3800 | 2048W_3800 |
| BOOTRST | Clr | Clr |
| CKDIV8 | Set | Clr |
| CKOUT | Clr | Clr |
| SUT_CKSEL | INTRCOSC_8Mhz_6ck_14ck_65ms | ExtXOsc_3Mhz_8Mhz_16KCK_14CK_65ms |
Note Full Swing Crystal Oscillator will only operate for VCC = 2.7 - 5.5 volts
| Setting | Default | Set |
|---|---|---|
| Extended | 0xFF | 0xFF |
| High | 0xD9 | 0xD9 |
| Low | 0x62 | 0xFD |
ToDo
Explore WatchDog Timer and set fuse WDTON - “Watchdog Timer Always On” -
http://tushev.org/electronics/arduino/item/46-arduino-and-watchdog-timer
http://www.jasoncavett.com/2011/03/accessing-watchdog-timer-on-arduino-uno.html
Arduino
Arduinio Software Serial library doesn't support 4mhz clocks - so I created a SoftwareSerial4Mhz with just a 9600 baud line - not yet tested
Arduinio wiring.c does not support 4Mhz clocks, so delays in the code will be wrong - either edit your delays (/2) or edit wiring.c
Added a section to boards.txt to tell the Arduinio IDE about the board:
############################################################## HabTrk.name=HabTrk (1.8V, 4 MHz) ATmega328 HabTrk.build.mcu=atmega328p HabTrk.build.f_cpu=4000000L HabTrk.build.core=arduino HabTrk.build.variant=standard
Added a section to programmers.txt to tell it about my serial Olimex AVR-ISP500, or you can just flash the hex file directly from Atmel Studio.
avrispmkiis.name=AVRISP mkII Serial avrispmkiis.communication=serial avrispmkiis.protocol=stk500v2
Checking
Checked frequency of transmission by measuring the pulse width - http://ssreng.com/how-do-i-know-the-baud-rate-of-the-serial-data/