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Zybo Z7 and Pmod OLEDrgb: Xilinx SDK issue


More newbe questions. I appreciate all of your patience and help, and the saga continues.

I have purchased a PmodOLEDrgb to explore AXI bus and the Pmod ports on your boards. To this end I am following the instructions on the Youtube video:

https://www.youtube.com/watch?v=kb2bOUv77Qc    Titled: Show and Tell Ep. 14 - Plug and Play Pmod IPs on Zybo and Arty.

I have successfully completed the instructions using a CmodA7-15 with a Microblaze. I am now attempting the same feat with my Zybo-Z7- 20. Following the video, as best I can, I can program the Zybo using the example in the video, but when I run as:(debug mode), the program just doesn't work. The same behavior occurs using various JP5 jumper setting. With the JP5 in the QPSI setting, the program seems to run, but jumps to the default program before displaying anything on the screen.

Looking thru the console messages I see:

Description    Resource    Path    Location    Type
comparison between signed and unsigned integer expressions [-Wsign-compare] PmodOLEDrgb_selftest.c    /ZyboPmodOLD_v1_bsp/ps7_cortexa9_0/libsrc/PmodOLEDrgb_v1_0/src\
  line 57    C/C++ Problem

Well this can cause problems when comparing results:  http://subethasoftware.com/2017/12/01/c-warning-comparison-between-signed-and-unsigned-integer-expressions-wsign-compare/ and I decided to print out these values just for fun to see these values at line 55 in the PmodOLEDrgb_selftest.c file.

xil_printf("PMODOLEDRGB_mReadReg = %d\n", PMODOLEDRGB_mReadReg (baseaddr, read_loop_index*4));
xil_printf("read_loop_index+1 %d\n", (read_loop_index+1)*READ_WRITE_MUL_FACTOR);

altho it compiled, I got the following warning:

Description    Resource    Path    Location    Type
...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'    PmodOLEDrgb_selftest.c    /ZyboPmodOLD_v1_bsp/ps7_cortexa9_0/libsrc/PmodOLEDrgb_v1_0/src    line 55 C/C++ Problem

I didn't realize the were guardians of the 'for' statement. Sounds like a good plot for a movie.

I have some questions about all of this.

1. Where does the xil_print statement put the output? Ran the newly compiled program and can find the values anywhere.

2. The console message disappear after it compiles. Where can I read the console messages after they are gone from the screen?

3. Is there any insight to getting it working on the Zybo. I include my block design.

Again many thanks for your help.





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Hi @rzsmi,

Here is a good xilinx Youtube video for using the SDK debugger.  xil_print sends data over the usb uart. To see the output I typically use a serial terminal emulator like tera term to connect to the usb uart bridge through a com port. 

Here is a good book dealing with ZYNQ and here is the getting started with zynq tutorial that should be helpful as well.

best regards,


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