Changes between Version 180 and Version 181 of GSoC/2015

Jul 28, 2015, 3:14:34 PM (4 years ago)
Jarielle Catbagan

Added status update for June 21, 2015


  • GSoC/2015

    v180 v181  
    184184* July 14: The DDR3 memory is now initialized.  According to the AM335x TRM, Section 2.1 "ARM Cortex-A8 Memory Map", Table 2-1 "L3 Memory Map", DDR memories can span the range 0x80000000 - 0xBFFFFFFF.  Prior to initializing the DDR3 memory, accessing a value within the memory space would result in a data abort exception to occur.  Now that it is initialized, I have been able to manipulate values within the DDR3 memory space but nothing useful just yet.  Now that the DDR3 is initialized, my next step is to set up the MMC interface in order to allow uMon to boot an application image from an external SD card and ultimately from the onboard eMMC memory.  With the MMC interface mechanisms in place, booting RTEMS applications will be just a matter of time before it is achieved.
     186* July 21: Currently implementing the SD/MMC interface.  I am focusing first on the SD card interface and since the interface to SD and MMC are quite similar, implementing MMC is not far off.  In order for the AM335x to connect to the SD card and perform communications, the SD/MMC/SDIO subsystem has to be initialized appropriately.  As a result the controller that will handle communications between the AM335x and SD card must have the timing and protocol configured properly.  For my reference in setting up the SD controller on the AM335x and to understand what is required to interface with an SD card I am using the AM335x TRM, Section 18 "Multimedia Card (MMC)", Physical Layer Simplified Specification Version 2.00, and SD Host Controller Simplified Specification Version 3.00.
    186188== Sujay Raj ==