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Forum Index : Microcontroller and PC projects : Programming 32MX170F
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| TREVINSK Newbie  Joined: 12/06/2016 Location: AustraliaPosts: 4 |
I am seeking advice re programming the PIC322MX Micromite as per Geoff's Projects and Silicon Chip articles. I have absolute minimal knowledge of the Personal Computer(PC) and the PIC32 but have general electronic experience. It is believed the Micromite is programmed OK as the IPE screen tells me so and two chips have been programmed. However, when attempting to utilise the CP2102 consoles (Silabs, and again I have tried two) the Tera Term and MM Edit emulators suggest there is some connection between the emulator, the CP2102 and the Micromite but the transfer of program data fails. The serial COM port appears OK at 38400 Baud rate, no parity and no stop bit. Neither emulator wants to operate as expected from the Silicon Chip/Geoff's Projects articles, which I interpret as an indication that there is no data connection between the emulator, the PC, the CP2102 and the Micromite. A driver for the CP2102 was installed in the PC but I have no means of knowing how the CP2102 and the Driver connect. Any advice would be appreciated. |
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| matherp Guru  Joined: 11/12/2012 Location: United KingdomPosts: 10213 |
Start by checking the CP2102. Connect the TX and RX pins on the CP2102 together and then go into teraterm. Type a few characters and they should echo. If that works you know that the connection to the PC is correct. How is the Micromite wired? Make sure you have all the connections shown on page 9 of the Micromite manual correct. |
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boss Senior Member  Joined: 19/08/2011 Location: CanadaPosts: 268 |
@trevisk I had similar problem with W10 installed driver. I suggest to download driver from Silab. Work fine for 2102 and 2104 chip. |
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| TREVINSK Newbie Joined: 12/06/2016 Location: AustraliaPosts: 4 |
Hello Matherp and Boss, Thanks for your quick responses; the programming board accords with the referenced diagram. Tried connecting the Tx/Rx pins - no joy. My gut feeling is that the issue is one (or more) inside the PC, or perhaps the CP2102 units sourced from China. Have reloaded drivers and programs for the Silab CP2102 but to no avail. Windows Device Manager tells me both CP2102's (in turn) are satisfactory!!!. Tera Term is able to discriminate between a connected and a disconnected CP2102. That said, I am wary of the Tera Term presentation. It does not present in the manner shown in the Micromite manual. Maybe the presentation is influenced by the presence of a connected Micromite. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10213 |
Until you get this working the Micromite is irrelevant. This should work with nothing connected to the CP2012, just TX and RX bridged. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1667 |
I have seen some weird things relating to USB/3, with devices often not behaving as expected. Swapping to USB/2 often resolves the issue. Both my laptops have both 2 & 3 and in some hardware configurations I think there is an additional driver layer. Cheers. |
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| TREVINSK Newbie Joined: 12/06/2016 Location: AustraliaPosts: 4 |
My thanks to all who contributed. Following Matherp's lead I find the Tera Term screen will only show keyboard characters when the CP2102 is plugged in AND (a) either the shorting clip is insitu between the CP2102 TX/Rx pins, OR (b) the PIC32 is connected to the CP2102. Removing the CP2102 from the USB port prevents keyboard characters appearing on the Tera Term screen. My education re the PC progresses slowly. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1667 |
Maybe what you were expecting to see is initially is what's referred to as "Local Echo". That's where what you type is displayed on the screen AND sent out the device port. What you type is displayed regardless of whether or not it gets to the receiving device. What Matherp suggested, is referred to as "Loop Back". So what happens is you type a character, it does not show on the screen, just goes out the serial port..... But as the TX & RX are now bridged, it comes back in again & is hence displayed on the screen, and instantly Once you are connected to the MicroMite a similar thing happens, a character goes out, the MM receives it & sends the same character back to be displayed on the screen, acknowledging that it received what you sent it. Hope that helps with an overall understanding. Cheers. |
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| TREVINSK Newbie Joined: 12/06/2016 Location: AustraliaPosts: 4 |
Good evening Phil23, Thanks for your response and description. As stated in my initial message, I am coming from a zero base of information and experience in respect of the PC and how it operates. Given that the loop back test seems OK, the next logical step is to determine whether data is arriving at the PIC32. I have previously checked out the various connections to the PIC, in terms of continuity, but maybe the oscilloscope needs to be dusted off. I will be tied up for a few days so will have time to think before I get to the next episode. Thanks again for your response. Cheers. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10213 |
If you have a scope that makes diagnosis easy. First, leave the serial port disconnected. Power up the Micromite with the scope on pin 11 with a trigger set at about 1.5V and you should see a sequence of bits triggering the scope as the Micromite outputs its Copyright Banner. If this doesn't happen there must be a wiring issue on the Micromite or it wasn't programmed correctly. Normal things to check are the capacitor on VCAP (lots of threads on what works best). Have a look at this thread for my personal approach on a breadboard. Also the connections to pins 27 and 28 are critical. If you do see the output then it must be the link to the CP2102. In which case make sure RX and TX are the right way round (RX on the CP2102 connects to TX on the Micromite) and the grounds are connected. It is always best to use a three wire connection (RX, TX, GND) to the USB adapter and have a separate 3.3V power supply to the Micromite. Then with the scope connected to pin 12 press and hold any key in Teraterm and you should see the bit sequence arriving. |
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