AVR Scope Clock Update



How to update the firmware on the Dutchtronix AVR Oscilloscope Clock Hardware 3-1:


The following information applies to the Dutchtronix AVR Oscilloscope Clock, hardware 3-1, firmware 3.5 and up, equipped with the ATmega328p AVR.


The firmware preloaded on the Atmega328p includes a bootloader compatible with the stk500v1 protocol. This bootloader is based on the Arduino bootloader (pre UNO) but reduced in size to only occupy 1KBytes, leaving 31KB for application programs! 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 AVR Clock, you will need a Serial Cable, connecting the AVR 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

The zip file above also contains the current V4.3 version of the Dutchtronix ScopeClock firmware.


The easiest way to connect the AVR clock to a PC is to use a standard DB-9 serial cable (DTE to DCE).


As an alternative, a custom Serial Cable can be made using a female DB-9 connector (for most PCs) and a 3 pin connector. This cable connects to the 3-pin polarized header marked RS232 on the clock PCB. Pin 1 is the right most pin. Wiring is as follows

3-pin connector - 1:GND,  2:out/RXpc, 3:in/TXpc.
DB-9 connector  - 5:GND,  2:RX,       3:TX.


If you installed the USB components on the AVR Clock board (these components are not included), you can connect the clock to a computer with a standard A-B USB cable. Make sure the FTD232RL drivers are installed on your computer. The AVR Clock board will present itself as a Virtual Serial Port. Make sure the serial port selection shunts on the AVR Clock board are set to USB


It is also possible to use a USB to Serial converter cable, though results are mixed.


Steps for updating the firmware on your AVR 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 AVR clock (the new firmware file).

  3. Make sure that no other program is using the serial port that is connected to the AVR clock, such as Bray’s Terminal, or worse, a GPS unit.

  4. 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.

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

  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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