LPC810 with PCF8563 I²C Real-Time Clock

A little circuit to try out the built-in I²C driver of the LPC810. Thanks to the Switch Matrix the I²C interface can be connected to the few available pins of the LPC800 Mini Kit board. The I²C driver is used in polling mode.

The on-board LED flashes once per second, clocked from the LPC810's internal timer, not the RTC. The RTC time is read once per second and transmitted on the serial port (115200n81). Its century bit is not used.

The RTC can be adjusted over the serial port by sending a string of the format hh mm ss dd MM yy D<CR><LF>, where:

hh = hours
mm = minutes
ss = seconds
dd = day
MM = month
yy = year
D = weekday (Sunday = 0, Saturday = 6)

The serial port is compatible with a 3V3 FTDI cable.

The software is an Eclipse project based on the LPC812 LPCXpresso LPCware library but adapted for the LPC810 Mini Kit. It must be compiled for release mode, otherwise the executable will not fit.

Project Elements

Circuit diagram as PNG (PNG, 257.85 KB)

LPCOpen_v1.02.zip (ZIP)

Eclipse project

Discussion (1 comment)

NECV20 10 years ago

I thought I give it try.

So I downloaded the project, started LPCXpresso with a nice clean workspace, imported the project(s) - I got four, and gave Expresso the order to build. 5 Errors and 42 warnings!!!

It seems that the IDE looks for all kind of files in the wrong places (not in the workspace map obviously) and board.h seems unfindable.

ClemensValens 10 years ago

Hello NECV20, What you see is a linker message that complains that it cannot find a library. I don't know why you get it, but the files you are looking for are included in the archive, to be exact, in the folder LPCOpen_v1.02\applications\lpc8xx\xpresso_projects\nxp_minikit_810\nxp_minikit_810_board_lib\ There you will find both release and debug versions of the library (dot a files). Did you do a project clean or did you delete parts of the unpacked archive? Do you do a "build all" or just build the current project (this is what you should do)? What do you have in your workspace? Anyway, the problems you are seeing are not so much NXP's nor LPC's fault, but the fault of Eclipse and probably mine because I did not provide an easier-to-use project (allthough it works fine for me in a completely new environment). It would be a shame to give up now, because all manufacturers of 32-bit microcontrollers provide their tools as an Eclipse derivative, so there is no escaping it. Of course everybody would gain a lot from a much simplified Eclipse, but that will probably remain just a dream. Please give it another try. Also have a look at http://www.lpcware.com/lpc800-mini-kit where you can find some tutorials. Regards, Clemens

NECV20 10 years ago

Hello Clemens, This works oké, well almost oké. This is the problem during build now; c:/nxp/lpcxpresso_6.1.2_177/lpcxpresso/tools/bin/../lib/gcc/arm-none-eabi/4.6.2/../../../../arm-none-eabi/bin/ld.exe: cannot find -lnxp_minikit_810_board_lib Something is missing, obvious again. Please help me out, before i loose faith in NXP and LPC. YS, NECV20

ClemensValens 10 years ago

Hello NECV20, Yes, yes - it is working. But you have to do the project import right. Eclipse is a hell/jungle and if you don't do it right, it won't work. Here is the right way of importing this project into LPCXpresso v7.0.2 (I just retried it): - Unzip the archive to a working folder on a disk - In LPCXpresso DO NOT use the Import project(s) from the Start Here menu. This option has the inconvenience that it does not allow you to UNtick the option "Copy projects into workspace". Use Import... from the File menu instead to work around this annoying default. (I probably should have created a more intelligent project archive, but as I said, Eclipse is a hell/jungle so please forgive me not knowing exactly how to do that) - Expand "General", choose "Existing Projects into Workspace" - Select root directory: browse to the folder [Your Folder]\LPCOpen_v1.02\applications\lpc8xx\xpresso_projects\nxp_minikit_810\nxp_minikit_810_rtc\ This will get you just one project to import, not four. Tick the project to import (nxp_minikit_810_periph_rtc) - Make sure that the option "Copy projects into workspace" is NOT ticked and click Finish When the import is done, set the project's Build Configurations -> Set Active -> Release (right mouse click on the project name). Now build the project (make sure it is the active project in case you have more than one project in your workspace) using the Start Here menu or the little hammer button in the toolbar. You should not see any warnings or errors. P.S. I seem to remember describing this procedure somewhere, maybe in the LPC800 webinar or in another LPC800 project on Labs, but I am not sure. Success! Clemens