Digital Discovery - Zybo interaction

[engrpetero]

I'm still working on correctly interfacing the DD to the Zybo and using the AXI QSPI driver.  Some unexpected behavior I'm hoping someone has an idea about.

I am using pmod JD for the desired signals (so from the QSPI outputs being monitored from the DD, CS is on pmod pin 2, SCLK is on pin 8, MISO is on pin 9, MOSI is on pin 10).

##Pmod Header JD                                                                                                                  
set_property -dict { PACKAGE_PIN T14   IOSTANDARD LVCMOS33 } [get_ports { DSPL_SPI_2 }]; #IO_L5P_T0_34 Sch=jd_p[1]                  
set_property -dict { PACKAGE_PIN T15   IOSTANDARD LVCMOS33 } [get_ports { DSPL_CS[0] }]; #IO_L5N_T0_34 Sch=jd_n[1]          // Chip Select for 420 char display				 
set_property -dict { PACKAGE_PIN P14   IOSTANDARD LVCMOS33 } [get_ports { TS_INT }]; #IO_L6P_T0_34 Sch=jd_p[2]              // Touch screen interrupt for graphical display    
set_property -dict { PACKAGE_PIN R14   IOSTANDARD LVCMOS33 } [get_ports { DSPL_GPIO_OUT[0] }]; #IO_L6N_T0_VREF_34 Sch=jd_n[2]       // Reset for 4x20 char display           
set_property -dict { PACKAGE_PIN U14   IOSTANDARD LVCMOS33 } [get_ports { DSPL_SPI_3 }]; #IO_L11P_T1_SRCC_34 Sch=jd_p[3]            
set_property -dict { PACKAGE_PIN U15   IOSTANDARD LVCMOS33 } [get_ports { DSPL_SPI_CLK }]; #IO_L11N_T1_SRCC_34 Sch=jd_n[3]            
set_property -dict { PACKAGE_PIN V17   IOSTANDARD LVCMOS33 } [get_ports { DSPL_SPI_0_MISO }]; #IO_L21P_T3_DQS_34 Sch=jd_p[4]             
set_property -dict { PACKAGE_PIN V18   IOSTANDARD LVCMOS33 } [get_ports { DSPL_SPI_1_MOSI }]; #IO_L21N_T3_DQS_34 Sch=jd_n[4]  

 

From the DD, I have input 24 monitoring CS, 25 monitoring SCLK, 26 monitoring MOSI, 27 monitoring MISO.

I'm also using a voltmeter and stepping through code using the VITIS debugger.  First issue, when I do not have the DD connected, the pmod pin 2 (CS) is high (3.3V) as expected.  When I connect the DD, pmod pin 2 measures 2.8V, not 3.3.  This without the debugger even running.

Any idea why this is happening (or something I've done wrong on the Protocol setup)?  I figure until I see the CS pin low using a voltmeter, I don't need to bother with the DD for debugging.

[attila]

Hi @engrpetero

Do you have proper ground connection between the devices ?
Is the VIO set to to 3.3V ?

[engrpetero]

yes.  and I have a black wire from the DD pin to the right of pin 27 connected to pmod pin 5.  I've tried it with Voltage Output (VIO) on and off both.  Still ways 2.88V.  When I turn on Voltage Output (VIO), I do see 3.3V on the DD red wires... 

 

[engrpetero]

With the DD still connected, I closed the Waveforms workspace and the voltage returned to 3.3V.  I reopened the workspace and the voltage went back to 2.88V.  I closed the Protocol and Logic panels that were in the workspace and reopened them.  Voltage stayed at 3.3V.  I saved the workspace, closed it, reopened it.  Voltage stayed at 3.3V.  It *seems* to be working now but now sure how it ever got in the 2.88V 'state' to begin with (or what might make it happen again).

Edited January 15 by engrpetero

[attila]

Hi @engrpetero

You are probably driving DIO24-CS from Protocol (or StaticIO or Pattern Generator)
The Protocol/SPI/Spy does not drive the specified SPI lines but the other Master,Custom... are intended for SPI master

[engrpetero]

That sounds reasonable.  I was playing with many different items still learning how best to use the DD.  Thanks @attila.