0 Replies Latest reply on Mar 22, 2011 9:20 AM by mdeazley

    Details of VRC 'double write' in RCCE

    mdeazley
      We're implemeting a power API in the SCC Development Framework. 

      In RCCE source file RCCE_power_management.c, function RC_wait_voltage(), the following lines appear when writing the
      voltage value for a given power domain in to the VRC:

      00582   // do it twice, see findings by Nikolias Ioannou
      00583    *RPC_virtual_address = VID_word(req->new_voltage_level, RCCE_voltage_domain(RCCE_IAM)); 
      00584    *RPC_virtual_address = VID_word(req->new_voltage_level, RCCE_voltage_domain(RCCE_IAM)); 

      This appears to make the core executing this code wait until the power has been 'set', but the details of this are not
      discussed in the EAS or the SCC Programmers Guide.

      Questions:

      1.) Is the processor halted/sleeping/waiting during execution of line 583?  If so how long?
      2.) Does it also wait at line 584? If so how long?
      3.) How does the commanding core 'know' the voltage has reached the commanded voltage setting? Please give hardware details.
      4.) The comment "do it twice, see findings by Nikolias Ioannou" preceeds the code... Where are these findings published?

      MJD