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Started by admin, November 30, 2006, 08:45:58 AM

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Andy Ayre

1. Before using these devices for the first time please be aware that the ISP entry method is completely different to the P89C51Rx2 family. Here is how it works (in brief):

  • The device is reset and starts looking for a 'U' on the RxD pin
  • If a 'U' is received within the default watchdog timeout period then ISP mode is entered and the bootloader autobauds to the 'U'
  • If a 'U' is not received within the default watchdog timeout period then the firmware in the device is executed
  • At 11.0592MHz the default watchdog timeout period is about 400ms

Therefore PSEN is not used.

2. If you select a P89C51Rx2 in Flash Magic, but you are actually programming a P89V51Rx2 or P89LV51Rx2, and you ignore the warning about the signature not matching, then you run the risk of placing the device into SoftICE mode. For information on the SoftICE mode search on this forum.

3. If you are trying to program one of these devices for the first time, go to Options -> Advanced Options -> Hardware Config and uncheck/untick the "Use DTR to control RST" option. When you click on "Start" it will tell you to reset the device. At that point reset the device and the window should close. Please see the manual and this forum for details on what the DTR option does and why it is important that it is correctly set for your particular hardware.

4. Before posting make sure you have read through and tried the suggestions in this post:

Posting the results of your tests will increase the chances that someone reading the forum will help you, and help you quickly.
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