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9 years, 1 month ago.
LPCXpresso11U68 UART overlapping
From what i can see the UART on arduino pins D1/D0(P0_18, P0_19) is used as the virtual serial port over USB? I am going to use a GPRS shield witch requires UART communication and uses D1/D0 and I would like to be debugging with printfs at the same time.
So my question is if there is a way to change the connections of the USB to serial? (I know this is possible on the Nucleo platforms)
Håkon
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1 Answer
9 years, 1 month ago.
There are two revision of LPCXpresso11U68 board and D0/D1 pins are connected to different ports.
| Arduino Shield receptacles name | Rev.B board | Rev.C board |
|---|---|---|
| D1 | P0_19 | P2_12 |
| D0 | P0_18 | P2_11 |
Virtual serial port over USB (USBTX, USBRX) are connected to same port of interface chip.
Please refer following document about the difference between Rev.B and C. http://www.lpcware.com/system/files/LPCXpresso11u68-revC.pdf
Possible options are:
Rev.B board
I think it's not easy to use the Seeed GPRS shield with virtual serial over USB (for debug log etc) due to the overlapping issue.
To do this:
- You have to cut the print circuit pattern between LPC11U68 and D0/1 pin (not between LPC11U68 and LPC4322)
- Solder between D0/1 pin to other UART channel e.g. UART4
Here is an example of GPRSInterface initialization code.
Serial pc(USBTX, USBRX); GPRSInterface gprs(P2_12, P2_11, 115200, "apn", "username", "password");
Rev.C board
No modification required for Rev.C board, but you must not specify D0/D1 pin name for Rev.C board since symbol names for LPC11U68 mbed SDK is defined for Rev.B board.
Serial pc(USBTX, USBRX); GPRSInterface gprs(P2_12, P2_11, 115200, "apn", "username", "password");
Please note that I didn't have both Rev.C LPC11U68 and Seeed GPRS board, so I didn't test actual connection between these boards. Also, I am not sure the Rev.C board is available in the market yet.
Assigned to 9 years, 1 month ago.
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Hi,
Just a quick question. Which revision of the board are you using? You can find a revision number in the back side of the board.
posted by Toyomasa Watarai 04 Mar 2015Hi, I haven't actually ordered one yet, just wanted to know if this was possible at the newest revision.
posted by Håkon Bryn 04 Mar 2015