USB2SER and BS2 programming
Brian Riley
Posts: 626
I have a question about the USB2SER ... it gets its power (+5) from the USB line from the host. So how does it know what voltage (3.3 vs 5) to supply to its TTL level TxD/RxD and RES lines? Or does it default to sending 3.3V down no matter what?
Am I correct in assuming the USB2SER could be used to program an 'naked' OEM BS2 family chip being run a 3.3v? (that is an OEM interpeter chip with no level shifting/inverting hardware attached to Sin/Sout) Would it run or blow if the OEM BS2 chip were run at 5 volts?
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cheers ... brian riley, n1bq, underhill center, vermont
Am I correct in assuming the USB2SER could be used to program an 'naked' OEM BS2 family chip being run a 3.3v? (that is an OEM interpeter chip with no level shifting/inverting hardware attached to Sin/Sout) Would it run or blow if the OEM BS2 chip were run at 5 volts?
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cheers ... brian riley, n1bq, underhill center, vermont
Comments
·· The FTDI Chip on the USB2SER has an I/O voltage pin that sets what voltage is being used on the I/O.· This pin is connected to the 3.3V from the internal regulator.· You can, however program 5V BASIC Stamp 2 OEM by using the following schematic.
http://forums.parallax.com/showthread.php?p=567989
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Chris Savage
Parallax Tech Support
csavage@parallax.com