http://www.kerrywong.com/2010/06/13/invoking-ds89c430-45-rom-loader-using-arduino/
Abstract
STEP1: Enable the Mode
Make RS-232/UART to USB COM port
B) PC’s USB port + USB-UART converter IC such as FTDI’s FT232R.
Please note that DS89C430/450’s RX pin is connected to the socket on the Arduino board marked with RX and the TX pin is connected to the socket marked with TX.
This is because Arduino’s RX socket is actually connected to the TX pin (pin 1) of FT232RL and TX socket is connected to the RX (pin 5) of FT232RL.
The picture below shows how this is setup between an DS89C430 and Arduino (I used an external 5V supply here for the DS89C430 board, but you can use the 5V pin directly from the Arduino board if you want to).
To make the selection of crystal frequency easier, I developed a spreadsheet that can be used to determine which standard baud rate a particular crystal can operate under. You can simply plugin the crystal frequency you intend to use and the supported baud rates are automatically highlighted in green (see screenshot below).
Baud Rate, Crystal Frequency Calculation
This spreadsheet can be downloaded here:
baudratecalc.ods (OpenOffice)
baudratecalc.xls (Excel)
The crystal frequency I used is 21.7 Mhz which as you can see in the screenshot above supports most of the standard baud rates.
Start Serial Communication
I use PuTTY for the serial communication with the following parameters (note the speed must be one of the supported baud rate calculated above, it depends on the crystal you use).
You can use gtkterm as well.
Serial line to connect to: /dev/ttyUSB0
Speed: 115200
Data bits: 8
Stop bits: 1
Parity: None
Flow control: None
And here’s a screen shot of DS89C430 in ROM loader mode:
Finally: Dumping ROM!
When the microcontroller is in ROM loader mode, programs can be uploaded using the ROM loader command interface mentioned in the user guide.
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