How to update the firmware on the Sparkfun Oscilloscope Clock V1.1:


The firmware preloaded on the Atmega328p includes a bootloader compatible with the stk500v1 protocol. This bootloader is based on the Arduino bootloader but reduced in size to only occupy 1KBytes, leaving 31KB for application programs! More than enough space for the current combined Clock/Terminal/Function Generator. The programming tool avrdude, part of the free WinAVR suite of programming tools, is used to upload firmware from your computer to the clock board.


Firmware is delivered in the form of an Intel Hex file (extension .hex). This file is a specially formatted text file. Do not change the file! The latest firmware file is listed here on the AVR Oscilloscope Clock main page.  Please download this file and store it in a convenient location on your computer.


To update the firmware in your Sparkfun Clock, you will need a Serial Cable connecting the Sparkfun clock to a PC, and the program called “avrdude”. This program is part of the free WinAVR release. Download the zip file below to get the required tools.

AVR Clock update tools: uploadm328p

Connect the Sparkfun clock to a PC using a standard DB-9 serial cable (DTE to DCE).  It is also possible to upload the firmware using an FTDI USB to serial converter cable or the Sparkfun FTDI breakout board. Make sure the serial port selection switch is set to USB.


Steps for updating the firmware on your Sparkfun Oscilloscope clock on a Windows machine:


  1. Open a command window (aka Dos box), cd to the directory where the downloaded zip file was extracted,
    for example "cd c:\uploadm328p"

  2. Edit the batch file uploadm328p.bat. Set the variable COMPORT to reflect the port you're actually using and set the variable HEXFILE to reflect the location of the hex file to be uploaded to the Sparkfun clock (the new firmware file).

  3. Use the On-Off switch to power cycle the clock (power off) and push and hold the push button switch S1 down while turning on the power.

  4. The clock hardware will now be in boot load mode (the LED D2 TO BE UPDATED is flashing fast), and no image is displayed.

  5. Make sure that no other program is using the serial port that is connected to the Sparkfun clock, such as Bray’s Terminal.

  6. Execute the batch file uploadm328p.bat from the command windows.


You can leave the boot loader mode, e.g., if you change your mind, by pushing the S2 button switch.


You can also upload firmware from non-windows computers if avrdude has been ported to that environment.


Due to limitations in avrdude, the verify option (-V) may need to been turned off in the script uploadm328.


For those customers able to directly program the Atmega328p using an AVR Programming device, please consult the FAQ for specific instructions.


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