using alternative serial port connection
I built the alternative serial port connection but I can not seem to program my propeller through the propeller tool. I specifically I have this:
Alt Ser Port Con as shown in the datasheet connected to a usb com port.
ground from that (p5) is connected to ground on the propeller chip board.
I am leeching 3.3v off of a lm2937et that is also powering my prop chip. so the 2937 is powering my prop chip and the ASPC.
I tell Propeller tool to identify hardware it scans com8 but does not see the chip. Do I need to do anything special? I have checked my breadboard a few times to make sure my alt connection was correct.
Alt Ser Port Con as shown in the datasheet connected to a usb com port.
ground from that (p5) is connected to ground on the propeller chip board.
I am leeching 3.3v off of a lm2937et that is also powering my prop chip. so the 2937 is powering my prop chip and the ASPC.
I tell Propeller tool to identify hardware it scans com8 but does not see the chip. Do I need to do anything special? I have checked my breadboard a few times to make sure my alt connection was correct.
Comments
I am very new to Prop, but I think Page 18 of the manual is worth another look.
If I am wrong then I will have learnt something
ron
Introducing the Propeller Chip
Page 18 · Propeller Manual v1.0
Boot Up Procedure
a. Detects communication from a host, such as a PC, on pins P30 and P31. If
communication from a host is detected, the Boot Loader converses with the
host to identify the Propeller chip and possibly download a program into
Main RAM and optionally into an external 32 KB EEPROM.
Back in my box...Alternative as shown on data sheet....not alternative as in pins!
It possibly seems that one can not use an usb-com port adapter with this alternative wiring
You do not need to do anything different to tell the IDE that its an alternative connection ...
The alternative works without issue with any USB to serial devices I have used ..
when you say alternative is that with the transistor circuit or using a circuit with an ST3232 IC or equivalent·?
Regards,
John
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'Necessity is the mother of invention'
Post Edited (QuattroRS4) : 12/12/2007 1:26:22 AM GMT
There was some talk a while back that C1 would be either a 10nF or 0.1uf capacitor
Read this thread ..
http://forums.parallax.com/showthread.php?p=585009
also Elektor did a variant of this some time back ..
www.elektor-electronics.co.uk/magazines/2007/july-august/serial-interface-for-the-propeller.197581.lynkx
Hope it helps ..
Regards,
John Twomey
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'Necessity is the mother of invention'
Post Edited (QuattroRS4) : 12/12/2007 1:26:00 AM GMT
I will change things to be similar to http://forums.parallax.com/forums/default.aspx?f=25&m=123910
I am using a .1uF cap.
Thank you for the assistance.
The Propeller Tool sets the speed to 115.2 Kbps with no flow control and the Propeller responds with the same as it receives. The data is encoded, one bit of data per byte (for control info) or 3 bits of data per byte (to download the program). The reason for this is that the Propeller's boot loader is running with the internal RCFAST clock which isn't accurate enough to do serial timing, so a ratiometric technique is used.