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Prop Serial Port Programmer Question — Parallax Forums

Prop Serial Port Programmer Question

DroneDrone Posts: 433
edited 2009-11-12 14:59 in Propeller 1
I built the serial port programmer from the Propeller Data Sheet V1.2. Propeller tool doesn't see the propeller on COM1. COM1 is set in control panel to the default 9600,8,N,1 no flow control. Should these settings be changed? The DC voltages seem correct on both sides of the serial port programmer. I've Ohm'ed out the cables and the connections seem correct. I've scoured the Propeller Manual, Data Sheet, and Unofficial Wiki and can't seem to find an answer to this. Before I break out more test equipment tomorrow I thought I would toss this out and see if anyone has a suggestion.

Regards, David

Comments

  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-11-11 17:27
    I use a simular cct, but with·a third transistor to·invert the DTR for the reset line. I got the cct from a copy of Elektor but I have seen it in other places.

    I do not know if it is the inversion and hence the other edge of DTR being used that makes the difference, or if it is just a better pulse shape/width/timing.

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  • DroneDrone Posts: 433
    edited 2009-11-12 13:50
    Thanks for the reply Toby,

    What are your serial port settings when using the Propeller Tool to program the prop? I see no way to set the serial port rate etc. in Prop Tool, so it must auto-baud I assume? What about flow control settings?

    Tnx, David
  • BradCBradC Posts: 2,601
    edited 2009-11-12 13:56
    Drone said...
    Thanks for the reply Toby,

    What are your serial port settings when using the Propeller Tool to program the prop? I see no way to set the serial port rate etc. in Prop Tool, so it must auto-baud I assume? What about flow control settings?

    Tnx, David

    115200 baud. No flow control. DTR is used in a short (~10ms) pulse to reset the prop, although I believe the Propeller Tool can be configured to use the RTS line instead if you are wired that way.

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  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-11-12 14:59
    As Brad says, the default that PropTool and BST opens with. I assume that it is 115200 Baud and I have never used anything but RX, TX, DTR and ground, so no flow control. The only times I have had serial problems were when I had (TTL) RX and TX reversed ie P30 + P31·( the old "from where are you talking" problem ) and when I stuffed 9 Volts up the Prop, it then chose not to talk to me, ever.

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