Display Data

Discovery

Hi,

I write literally scores of programs for the Basic Stamp controller and for most of them they control an apparatus. When I need to monitor the process, I connect my laptop to the BS2 via the USB, open a Debug window, select a port and the data begins painting the screen.

However, for Propeller programs when I disconnect the USB cable and take the laptop away for other activities then return to monitor the data...as soon as the USB cable is connected to the computer the Propeller program stops. In order to get data...I must download and start the program which messes up the controlling process.

Is there an easy way to prevent the Propeller program from stopping when the USB cable is reattached and have the Propeller act like the BS2 controllers?

Sincerely,

Discovery

Electrodude

What board are you using?

If you're using an external Prop Plug, you can plug the USB into the Prop Plug before pluging the Prop Plug into your Propeller board. If your board has an on-board USB-Serial converter, you can probably still do this by connecting a Prop Plug to the right pins and not using the on-board converter.

Chris Savage

In some cases connecting a BASIC Stamp Board also results in the MCU being reset since, while being enumerated, the FTDI chip tends to cycle the DTR line, which is attached to the reset pin on both MCUs. As Electrodude suggested, the Prop Plug can be connected/disconnected from USB separate from the MCU connection. But if you're using a USB programming interface, reset is a possibility.

Discovery

I have the Propeller Activity Board with the prop plug built in and several manufactured PC Boards with the prop plug module soldered to the boards.

I will try your suggestion.

Thanks

Discovery

Discovery

All I can do is connect/disconnect the USB at the computer or connect/disconnect the small USB at the prop plug.

I get the same results...MCU halt.

Discovery

Chris Savage

That is because when the FTDI chip is connected to the PC it is enumerated and is cycled several times. One thing you could do on a custom board is have a jumper on the /RES line so that when not updating firmware the Propeller chip can't be reset by the serial interface. That won't help on the Activity Boards, but on a custom board it's an easy design addition.

Bob Lawrence (VE1RLL)

You might want to check your USB device driver (under devices) in the control panel and ensure you have the latest version and that it is setup correctly as per the Parallax instructions on their web site.

also do other Prop heads have this problem?

Bob Lawrence (VE1RLL)

For example here's the fixes the latest update did . The FTDI website may have an even later update.

Version 2.10.00

Supports Windows XP/Vista/7/8/8.1. (XP and Vista are supported but are not Microsoft Certified since Microsoft ended their certification support for those operating systems). For other FTDI USB drivers see http://www.ftdichip.com/Drivers/VCP.htm. Installer available as .exe and .zip archive.

Fixes Included Since v2.08.24:

Support for Selective Suspend
Support for Windows 8/8.1
Performance improvements on open and close port
Fixed problem where COM port became unavailable after D2XX port access
Fixed synchronization issue that could lead to data loss
Fixed bug on close port for .NET Framework applications
Fixed problem on close port that caused some hubs to fail
Fixed bug that prevented remote wakeup for composite devices
Fixed bug causing wrong number of bytes written to be reported after a timeout
Fixed bug in VCP XON/XOFF flow control
Fixed problem connecting multiple devices to EUSB adapter

Cluso99

This is a known problem with parasitic power flowing through from the prop serial output pin P30 that partially powers the FTDI chip when there is no USB connection.

If you can disable the output pin P30 (ie DIRA[30]~ ) or stop the serial driver on the prop (eg FullDuplexSerial) when the USB is not connected this should prevent the problem.

If you can cut the P30 trace to the FTDI and insert a 5K-10K this may help.

If you can cut the DTR trace to the transistor base this may help.

Discovery

Thanks Cluso...disabling P30 in some fashion is my next step.

Sincerely,

Discovery