XCORE-XA Module

[Folknology]

I notice that the SPI flash uses pins 1A-1D, these pins are also exposed on the header, I need as many 1 bit ports as possible but am worried about using these (particularly 1B) as they might compromise the Flash, is this issue dealt with using a mux (like slicekit) or some other method, the manual does not specify or highlight anything about this. Unfortunately the manual does not include a schematic for me to check this myself.

PS I cannot locate ports 1I and 1J where are these hiding?

regards
Al

[mon2]

Hi Al. Some mixed news. Here are the 1 bit port mappings for the XCORE-XA module.

X0D00 = P1A0 = J1_D0 (Pad 5) = U2_SO_Pin2 SPI = no mux & shared connect with both locations
X0D01 = P1B0 = J1_D1 (Pad 6) = free to use = also connects to R55. R55 is a no stuff (bottom PCB)
X0D10 = P1C0 = J1_D10 (Pad 7) = U2_SCK_Pin6 SPI = no mux & shared connect with both locations
X0D11 = P1D0 = J1_D11 (Pad 8) = U2_SI_Pin5 SPI = no mux & shared connect with both locations
X0D12 = P1E0 = J1_D12 (Pad 19) = free to use
X0D13 = P1F0 = J1_D13 (Pad 24) = free to use if J15 = HDR else P1F0 will drive cathode of LED D4
X0D22 = P1G0 = J9_D22 (Pad 5) = free to use
X0D23 = P1H0 = J9_D23 (Pad 6) = free to use
X0D34 = P1K0 = J9_D34 (Pad 7) = free to use
X0D35 = P1L0 = J9_D35 (Pad 8) = free to use
X0D36 = P1M0 = J1_D36 (Pad 21) = free to use
X0D37 = P1N0 = J1_D37 (Pad 20) = free to use
X0D38 = P1O0 = J9_D38 (Pad 19) = free to use
X0D39 = P1P0 = J9_D39 (Pad 20) = free to use

No P1I0 and no P1J0 are present. Hope this helps.

[Folknology]

Hi Mon2

Thanks, Are you saying 1B is only connected to R55 and is not populated. Normally 1B is connected to SS on the flash and is pulled up via a resistor. The XN file definitely suggest this pin is in use, if no mux then maybe jumpered?

Code: Select all

...
<Nodes>
        <Node Id="0" InPackageId="0" Type="XS1-L8A-64" Oscillator="48MHz" SystemFrequency="500MHz">
          <Boot>
            <Source Location="SPI:bootFlash"/>
          </Boot>
          <Tile Number="0" Reference="tile[0]">

            <Port Location="XS1_PORT_1A" Name="PORT_SPI_MISO"/>
            <Port Location="XS1_PORT_1B" Name="PORT_SPI_SS"/>
            <Port Location="XS1_PORT_1C" Name="PORT_SPI_CLK"/>
            <Port Location="XS1_PORT_1D" Name="PORT_SPI_MOSI"/>

          </Tile>
        </Node>
      </Nodes>
...

[mon2]

Hi Al.

P1B0 is connected to the R55 pad and also same connection is connecting J1_D1 (Pad 6). R55 is not stuffed on the board we have here. This part appears to be 0402 size and on the bottom side of the PCB.

Other side of R5 is connecting to U2_Pin1 (#CS_SPI Flash). This same pin1 (#CS) is pulled up through R13 (10K) to +3.3 volts. This will result in default of SPI = OFF.

Noting the above wiring, confused on the use of this external flash. Without R55 being stuffed, how can this external flash even be enabled ? Curious to know if you have attempted to store any self-boot code inside this external SPI flash ? Will attempt the same later today or at the work tomorrow.

At this time of writing, looks like a missed and important component. The pads look small so a small blob of solder could correct the enable pin. That is, then P1B0 would serve its purpose during SPI boot using this external device. Welcome your comments.

[pstnotpd]

Hardware manual...

It says there's a REV2 version of the board.

[Folknology]

I think the shipping XCORE-XA Modules are all Rev 2

[mon2]

The module received here through Digikey is marked with Rev 2.

Anyone have success to use this external SPI flash (U2) to boot their XCORE code ? With R55 missing, having some doubts if it is even possible to enable this external flash.

[Folknology]

For me in this application it is a good thing as I need all of the 1 bit ports I can get hold of. However it does seem strange shipping the module with external SPI flash that you cannot use without soldering an 0402 resistor. I wonder if we are missing something..

regards
Al

[EdB]

The expected usage is to boot the xcore from the internal ARM flash, removing the requirement for the external flash and allowing the use of all of the exposed 1b ports.

The external flash is there in case you want to boot the xcore without booting the ARM. If you want to use it you will need to bridge R55 (solder blob is pretty easy with 0402 pads).

[Folknology]

Thanks Ed that clears it up, it certainly works for me.

regards
Al