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The Question for ADuC7020 download program

we adopted ADuC7020 and ADM101E for the program download from Keil to ADuC7020.The schematic of circuit as follows:

when we download the program to the chip.we turn BM/P0.0 from high level to low level,as shown from 1 to 2 in Figure.but the software ARMWSD show the follows:

program can not download to chip,and false code are displayed in the panel.

what's wrong with our schematic,can you give me some suggestion,thanks.

  • Hi zhoujx,

    I can comment on the RS-232 part of your circuit.

    Others might be able to comment on the ADuC7020 circuit.

    The ADM101E data sheet Figure 1 shows the recommended 0.1uF capacitors between;

    Pin 1 and Pin 10

    Pin 2 and Pin 9

    Pin 3 and Pin 1

    In your schematic I can only see a 0.1uF capacitor between Pin 2 and Pin 9.

    Best Regards,


  • Hi zhoujx,

    Is the ADuCM7020 actually in download mode?

    The part must be reset or power cycled while the BM pin us held low.

    If you look at the SIN and SOUT lines with a scope do you see any noise or data being transmitted?

    From the screenshot it seems that there's quite a lot of data being sent by the ADuC7020 so from an ADuC7020 side it's either


    1.      There's code on the part that toggles the SOUT line and the ADM101E and the PC sees that as communication or
    2.      there is noise on the line and the ADM101E and the PC see this as communication



  • Hi Richard,

    I checked RS-232 to PC by software of CommUART Assistant,which shown the connection is intact.

    For the ADM101E data sheet Figure 1,I think 0.1uF capacitors between Pin 1 and Pin 10(or Pin 3 and Pin 1) only filter ripple of power supply,which have no significant effect on the function of the ADM101E.Also,we used non polar ceramic capacitor instead of polar tantalum capacitors. Do you think the type of capacitors influence the function of ADM101E?

    Best Regards,


  • Hi Zhoujx,

    Using the datasheet recommended decoupling capacitors will mean that the ADM101E operation will be more stable.

    But it looks like your communication issues may be with the ADuC7020 as I can see from the other posts.

    Best regards,