Setting of non-standard baudrates

[StM]

it would be very helpful if flash magic support non-standard baudrates, too. So the user can choose the best fitting baudrate for his design. For production purpose a maximum baudrate of 38400 (in case of an LPC221x with a 12MHz crystal) is not really satisfying.

[erikm]

what good would that do?
how do you propose to make a Windows PC spit out 'non-standard baudrates'

Erik

[Andy Ayre]

Unfortunately Windows only supports specific baudrates.

Andy

[Jan Waclawek]

Unfortunately Windows only supports specific baudrates.

Well, this is not quite true - any baudrate can be specified in DCB structure used in WinAPI to set serial devices' properties; however, it depends on the particular device's driver how does it interpret. See for example here: "BaudRate  The baud rate at which the communications device operates. This member can be an actual baud rate value, or one of the following indexes."

However, there is no standard method to discover, which particular baudrates are actually supported by a given COM port; on the other hand, there barely exists any form of serial port not supporting the "standard" baudrates, hence they are considered safe to use. If I would implement such a function, I would not expose it in the front window; rather, I would hide it somehow in the "advanced" functions.

JW

[whitewing]

Unfortunately Windows only supports specific baudrates.

Andy

USB-Serial devices, e.g. the FTDI parts, typically support a large range of baudrates beyond the traditional set.

[whitewing]

Something else you can do with the FTDI devices is set up 'aliased' baudrates, which map Wnndows COM port rates to different actual rates at the far end of the USB link. For example you can configure it so that when you say 300 baud to Windows, it actually sets 1mbaud. This is done by tweaking the divider value table in ftdiport.inf - there are a couple of FTDI apnotes on the subject.
 
 

[pfaltynek]

Although after some time, I would also vote for having ability to set user baudrate. Just let the combobox be also editable and when user enters "non-standard" baudrate (which means baudrate you don't know) just issue a warning but do not disallow it, just pass to the com init structure. This would be helpful for us too. We had to implement own flash tool supporting 125000/250000 baudrates (suprisingly working ).

[Andy Ayre]

The command line interface for Flash Magic allows any baudrate of 600 baud or greater. Let us know if you run into problems.

Considering Jan's comments above we think the best place for this potential trap is in the command line interface, which is typically used by advanced users.

Andy