Hello, I need a help. I have AT89C51ED2 and FLIP programmer. But even if a have connected PC through RS232, nad through MAX 232 to processor I am not able to program it. If I select device and comunication a try to connect.It shows a message Timeout Error. Its on pins Rx and Tx. Is necessary to set any other pins to any voltage? Thank you very much. Cya TomZ
Hi, 1. Activate RST 2. Short the PSEN pin to GND 3. Deactivate RST 4. Release PSEN For further info, Atmel's data sheet http://www.atmel.com/dyn/resources/prod_documents/doc4257.pdf page 102 says the following:- The bootloader can be activated by two means: Hardware conditions or regular boot process. The Hardware conditions (EA = 1, PSEN = 0) during the Reset# falling edge force the on-chip bootloader execution. This allows an application to be built that will normally execute the end user's code but can be manually forced into default ISP operation. As PSEN is a an output port in normal operating mode after reset, user application should take care to release PSEN after falling edge of reset signal. The hardware conditions are sampled at reset signal falling edge, thus they can be released at any time when reset input is low. To ensure correct microcontroller startup, the PSEN pin should not be tied to ground during power-on (See Figure 43). Hope this helps, Mark.