Shawn: Created page with "==Connecting PICAXE to computer== ===Inverting serial logic=== One difficulty in integrating PICAXE into your lab is that its serial device is inverted from the normal TTL log..."

2014-03-01T23:07:53Z

Created page with "==Connecting PICAXE to computer== ===Inverting serial logic=== One difficulty in integrating PICAXE into your lab is that its serial device is inverted from the normal TTL log..."

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==Connecting PICAXE to computer==
===Inverting serial logic===
One difficulty in integrating PICAXE into your lab is that its serial device is inverted from the normal TTL logic, so that it can be programmed cheaply via a standard, 15V RS-232 port with resistors to bring the signal's voltage to 5V. You may use other serial devices that use standard TTL logic to communicate to a computer via a TTL<>RS232 or TTL<>USB circuit, but you'll have to use one of the following solutions to make sure the logic is the proper flavor.

====Alter firmware of FTDI chip====
You can use a Windows computer to reprogram an FTDI USB<>TTL chip to invert the logic properly, after which you can use the chip with any OS, including MAC. See http://www.ftdichip.com/Support/Documents/AppNotes/AN_124_User_Guide_For_FT_PROG.pdf for instructions on how to use FTProg, FTDI's programmer. See http://letsmakerobots.com/node/19013 for specific instructions on how to switch the logic. See http://www.ftdichip.com/Support/Utilities.htm, see http://www.ftdichip.com/Support/Utilities.htm#FT_Prog for a download link to the utility. FTDI warns that using this utility may render the hardware unusable.

====Use an inverter IC====
You can use a logic inverter chip to switch the logic of the serial lines. See http://letsmakerobots.com/node/21245 (or http://www.patrickmccabemakes.com/PatrickMccabeMakes/FTDI.html ) for instructions.

===Programmed communications can be either flavor===
This is not a concern with programmed serial communications, since you can choose to invert, or not, serial communications during operation with the configuration parameter "baudmode". For example, SEROUT 2, N2400_4(b1) outputs to pin 2 the value of input b1, at 2400 baud when the chip is running at 4MHz, with idle (logical 0) low; SEROUT 2, T2400_4(b1) would do just the same but with idle high, a low voltage indicating a logical 1. T stands for TRUE, the standard mode most systems such as Arduino use.

[[Category:Electronics]]

PICAXE serial - Revision history

Shawn: Created page with "==Connecting PICAXE to computer== ===Inverting serial logic=== One difficulty in integrating PICAXE into your lab is that its serial device is inverted from the normal TTL log..."