FLASHMON: Configuring AT89C51SND1 Development Kit

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Information in this article applies to:

• C51
• Atmel AT89C51SND1 Development Kit

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QUESTION

I am using the Atmel AT89DVK, a development board for the AT89C51SND1. I have read Application Note 174: "Use FlashMon on AT89C51SND1" which was written for this board.

I followed the instructions in this application note, but I am unable to get Flashmon to connect to my board.

• Download the MONITOR.HEX onto the AT89DVK board using the Atmel FLIP utility.
• Toggle the ISP switch on the AT89DVK.
• Perform a hardware reset to start FlashMon.
• Select Peripherals -> "Start Debug Session".

I receive the following error:

CONNECTION TO TARGET SYSTEM LOST

What am I doing wrong?

ANSWER

The hardware on the AT89DVK development board differs from the demo board that was used in the application note. Additional steps are required to get the board up and running.

A true RS-232 transceiver must be between the PC and the AT89DVK development board. One option is a MAX232 or equivalent chip. Another option is to use a RS232 to Logic Level Serial Converter cable.

Finally, the default XDATALEN value in the startup.a51 file must be changed from:

XDATALEN    EQU 800H    ; the length of XDATA memory in bytes.

to:

XDATALEN    EQU 400H    ; the length of XDATA memory in bytes.

The FLASH monitor from KEIL requires XDATA (either internal XRAM or external XDATA). Changing the above setting prevents the startup code from erasing all of the internal XRAM, including the XRAM memory used by Flashmon. The upper XRAM memory, which is used by Flashmon, will be preserved.

The files attached to this article contain:

• A Flashmon project configured for the AT89DVK development board
• A test code sample project for the AT89DVK development board
• A schematic for the RS232 circuit required for the board

MORE INFORMATION

• Refer to Application Note 174 for more information on how to use FlashMon on the Atmel AT89C51SND1.
• Refer to Atmel's documentation of the AT89DVK-04 evaluation board.

SEE ALSO

• MON51: Connection to Target System Lost
• FLASHMON: Atmel Devices with External UART
• FLASHMON: FlashMon crashes while loading on Atmel Device

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ATTACHED FILES

Request the files attached to this knowledgebase article.

Last Reviewed: Thursday, February 25, 2021

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