AceOfHearts said:Basically,
I got these from www.active-robots.com, they said what you put in is what you get at the other end, provided baud rate is 19200. The data sheet claims the output can be connected directly to a TTL/CMOS device.
The problem is this. The output from the receiving tranceiver is +/-10V for some reason. This makes it unsuitable to go into my 8051 uC. However, I can get over that using a potential divider.
The bigger problem is this. I checked using the oscilloscope the signal received and compared it with the signal trasmitted. Now, I thought what you put in is what you get at the output. But this wasnt the case. Although the bit stream was identical, the time I was not trasmitting, the logic was 0 (-10V) when it is meant to be a logic 1 according to what I was transmitting.
My computers Terminal/hyperterminal therefore could not make sense of the data, nor could my uC
I had the baud rate of 19200 set on everything.
Any shed of light would be appreciated.
1. The module operates internally from an on board 3.3 Volt low drop regulator. The logic levels of the input/output pins are therefore between 0 Volt and 3.3 Volts. (See RS Performance Data).
2. All digital inputs and outputs are intended for connection to low voltage logic devices. Do not connect any of the inputs or outputs directly to an RS232 port. The receiver module may be permanently damaged by the voltages (+/- 12V) present on RS232 signal lines. See Application Circuit (Figure 11) for typical connection to an RS232 port via MAX232 interface IC.
Nigel Goodwin said:The datasheet says:
So the output from the receiver should be TTL/CMOS compatible, 0-3.3V or so. I suggest you consult Figure 11 and add a MAX232 if you want to feed directly to your PC.
Nigel Goodwin said:Post a picture of how you have it connected, presumably you're doing something wrong somewhere?.
AceOfHearts said:Ok, I will see what I can do.
Out of interest, have you ever used these devices?
ahmedragia21 said:ace, do you remember the codes i need =) ?
thanks
AceOfHearts said:Thanks for the responses.
Blueteeth, I tried connecting to the PC directly as well as using max232, nothing.
AceOfHearts said:I really am disappointed with my purchase, it cost me over £100
And I only noticed the transceiver modules on its own today. I would have been better off with those and saved fifty quid.
AceOfHearts said:Desoldering is not an option,too messy with little pin left. Active Robots have really done it this time, completely misleading customers with those data sheets. All the handshaking lines have been disabled too and the data sheet is irrelevant.
[/QUOTE]AceOfHearts said:Can you tell me whether those modules on their own work without an external antenna? What is the range? And can you connect TTL/CMOS on input and on output directly? Do they need anything else to work? Thanks.
AceOfHearts said:The baud rate is set at 19200 and I cant change it. Blueteeth, on the modules you have, were you able to change the baud rates?
AceOfHearts said:Also, Does the internal buffer HAVE TO be full before it transmits all the bytes? Or does it transmit as soon as it received the data?
Blueteeth said:Yet another edit - christ I've screwed this post up....
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