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Forum Index : Microcontroller and PC projects : Maximite Serial Port and "True" RS232
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| mookster1 Regular Member  Joined: 10/06/2011 Location: New ZealandPosts: 81 |
I've managed to get the Dorji modules to work! SO far I've managed to get text from my TRS80 sent to the Maximite over radio (no PICAXE between Maximite and the radio module) using a PICAXE20M as a level converter (it can operate at 9600bps and it can handle the +-12V supplied by a serial port). What I was doing wrong was that I was sending the radio modules data at a different baud rate to what they were expecting, so of course nothing was going to happen! For those familiar with PICAXE I'm using the SERRXD command to receive data from the TRS80 on the programming pins of the PICAXE20M but unfortunately the command doesn't time out, so unless you're constantly sending character "10" i.e. linefeed, which I'm using to indicate the end of a data string, the PICAXE20M just hangs when trying to receive serial data, and refuses to receive data from the radio module while doing so. That's only a minor issue however so I should be able to sort it out when I get time. Capacitance is futile - roll on 2012! |
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| aargee Senior Member  Joined: 21/08/2008 Location: AustraliaPosts: 255 |
The Picaxe 20M can handle +/- 12V? I don't think so... or at least not for long. see http://ww1.microchip.com/downloads/en/DeviceDoc/41262d.pdf section 17 - Rob. For crying out loud, all I wanted to do was flash this blasted LED. |
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| Greg Fordyce Senior Member Joined: 16/09/2011 Location: United KingdomPosts: 153 |
The picbasic pro has a good explanation of how to directly connect a microchip pic to RS232 without a level converter. Look at the serin and serout commands for a schematic. Picaxe is the same chip, so same principles apply. |
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djuqa Guru  Joined: 23/11/2011 Location: AustraliaPosts: 447 |
Living in the fast lane when chips such as the Maxim MAX3232 are cheap, reliable and work from 3.3v/5v VK4MU MicroController Units |
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| Greg Fordyce Senior Member Joined: 16/09/2011 Location: United KingdomPosts: 153 |
Life's more fun in the fast lane.  |
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| mookster1 Regular Member Joined: 10/06/2011 Location: New ZealandPosts: 81 |
With the PICAXE, its programming pins connect directly via a couple of resistors to a serial port. There's also commands which let you send/receive data on these pins (SERTXD and SERRXD.) This allows you to do basic debugging while you've still got the PICAXE plugged into the computer after you've programmed it. See here: http://www.picaxe.com/Site_Resources/Media/Site_1/pinout/ser ial.jpg. Note that the cable is just wires to the appropriate pins on the serial port. Capacitance is futile - roll on 2012! |
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