TMS320F28386D: EMIF block issue

Part Number: TMS320F28386D

Hello,
customers sees an issue with EMIF2 and external ADC connected to it.

  • The ADC is clocked via a GPIO and produces a new sample with each clock pulse. They read the value via the EMIF2 data lines.
  • The EMIF2 is configured in asynchronous mode, but only the data lines are used.
  • The ADC is the only device on the EMIF2 bus and during a sample series constantly drives the bus (output enabled).
  • The EMIF2 normally “parks the databus” after an asynchronous read.
    • They discovered that by seeing the databus having strange behaviour during the sampling process.
    • They were able to fix it by setting the Self-refresh bit in the SDRAM settings of the EMIF and doing a read cycle.
    • However, somehow the unwanted driving of the datalines by the EMIF has reappeared now, despite the described fix.

Question: is there a way, as described or otherwise, to make sure that the EMIF does not “park the bus”?

Regards, Holger