Arty Z7 + DMMShield + MTDSShield

[kwilber]

I extended the Arty Z7 DMMShield demo to use a MTDSShield. The touch screen was a natural for selecting the function and ranging and displaying the measurements.

This turned out to be a bit tricky for several reasons.

1. The DMMShield does not have a SPI pass through connector. I ended up using tall stackable connectors to provide enough clearance to use a cable from the Arty SPI connector to the MTDSShield SPI connector.
    
2. The DMMShield used IO10 for its SPI chip select which is also the default chip select for the MTDSShield. I  had to specify the alternate SPI chip select of IO8 for the MTDSShield in the constraints.
    
3. The Arty Z7 board definition has MISO and MOSI swapped as compared to the Arty A7 and S7 boards. I had to specify the correct pins in the constraints as described in this forum post. 
   
   You can see the swap if you compare the following section in the Arty Z7, Arty S7 and Arty A7 board.xml files and observe the logical to physical mapping for spi_miso and spi_mosi.

   <interface mode="master" name="spi" type="xilinx.com:interface:spi_rtl:1.0" of_component="spi" preset_proc="spi_preset">

    

[Bianca]

Hi @kwilber,

I'm sorry it turned to be such a challenge to interface the MTDS with the DMM Shield and Arty Z7

Indeed the CS form the SPI is used for the communication with the DMM Chip, also, the SPI is shared between the EEPROM and the DMM Chip. Just the CS are different. 

As for the swap between MISO and MOSI, it looks that we made a mistake and we are looking into it. I looked in the standard and it should be as it is on the Arty A7 and Arty S7.

Thank you for letting us know.

Best regards,

Bianca