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gorkin
Joined: 27 Feb 2002
Posts: 621
Helped: 9
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 11 Apr 2006 18:34 AVL with G20 Motorola GSM Module |
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Hi my brothers!
Anyone have experience with G20 GSM module for AVL application? I build one project with G20, Leadtek GPS module and PIC18LF6722, for power supply I use LM2576 ADJ step-down switching regulator...If anyone interested I can post the schematic here for give Your critics.
Thanks a lot, Gorkin.
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linoko
Joined: 25 Jun 2004
Posts: 38
Helped: 2
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| 13 Apr 2006 16:44 Re: AVL with G20 Motorola GSM Module |
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Hi Gorkin,
I'm very intereted about you project, please post you schematic and hex or source file i want to build one device to myself.
Best Regards Linoko
Sorry about my English
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Nightmare
Joined: 04 Dec 2005
Posts: 3
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| 13 Apr 2006 18:49 AVL with G20 Motorola GSM Module |
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Hi Gorkin,
It would be great if you could post the schematic as well as the code.
Thanks in Advance
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7rots51
Joined: 17 May 2002
Posts: 1348
Helped: 14
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| 13 Apr 2006 20:56 Re: AVL with G20 Motorola GSM Module |
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http://www.trimtrac.com/about/index.shtml
this company integrated GPS,GSM in one small module to present AVL that operates with 4 AA bat for 90 days and its size is like as mobile phones!
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Justins
Joined: 10 Jul 2006
Posts: 9
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| 10 Jul 2006 8:25 Re: AVL with G20 Motorola GSM Module |
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| If anyone is looking for GPS device with best quality and price - pm me
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gorkin
Joined: 27 Feb 2002
Posts: 621
Helped: 9
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| 22 Jul 2006 23:53 Re: AVL with G20 Motorola GSM Module |
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Hi brothers!
Forgive-me for long time between my questions above and the schematics post...But itīs necessary for exaustive evaluation and debbuging. Above, anyone can upload the latest schematic...
Now, I have some doubts:
(1). When I connect one satelital modem in serial USART, the microcontroller not receive any valid data from the external satelital modem, all data are corupted (its happens only with satelital modem, if I connect one PC Serial Port in serial USART board, serial communication function perfectly). Whats are wrong?
(2). U404 (Low DropOut voltage regulator) not delivery +2.80V in output, but more than +3.2V... I am suspect of distance between decoupling electrolyte capacitors and the IC, anyone have the same problem one time?
(3). When I using UART interface for communicating with G20 module and switch for communicating with USB interface (using one PC or PDA for example), the "host" USB not detect the USB "peripheral" (In my case, the G20 module). Reading the hardware manual interface of G20 module I founded that I must put all serial UART microcontroller pins in high impedance mode. In the schematic, this is acquire by disabling the SN74LVC244 buffer (after microcontroller detect by USBDT pin the presence of USB "host")...But I am not have any sucess. When I remove the SN74LVC244 buffer, the USB "host" detect the USB "peripheral" (in my case, the G20 module). Anyone have any information about the internal construction of the SN74LVC244 buffer? Itīs possible the internal construction of the gates offers low impedance for G20 serial circuits?
(4). The audio stage function, but maybe function well, anyone have other idea for this stage?
PS: My PCB board was realized with 4 layers...itīs really necessary? Because 4 layers is very expensive...
Thanks in advance, Gorkin.
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