On our C6745 based custom board, we are having some problems with booting from NOR flash on EMIFA. This is what I did and what I see.
One questions is that how does the ROM bootloader setup EMIFA? How does it know things like write strobe? In my code, I have AEMIF_A1CR = 0x08a4432C, but I bet the ROM bootloader doesn't know this.
I am pretty confident that the boot pins have been set up properly.
I found the answer to this problem. Boot3 and Boot0 had bad levels because their internal pull up/downs were the opposite of the required state for NOR boot. 20K external pullup/downs weren't strong enough to give the required level so the 6745 wasn't actually trying to boot from NOR.
A friendly reminder to everyone to beware of the internal pullups and pulldowns on boot mode pins! I measured them to be approximately 28K. External pullup/downs of 1K give good logic levels.
A clarification - Yan is working on a board that I designed, so the boot mode pins having bad levels is my fault! :)
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.