| ??? 01/17/05 10:12 Read: times |
#85077 - SDRAM maybe viable Responding to: ???'s previous message |
While I did not try myself, I am convinced SDRAMs can be directly connected to mcus with external data bus in general, but their access is not so straighforward and their tremendous speed will not be fully utilised by far. A not-so-simple logic inserted between the mcu and SDRAM would probably be able to hide the details from the mcu, enabling to access it as a simple SRAM.
Craig Steiner said:
It appears there is some kind of "refresh" cycle every 15us that would have to be worked in somehow? In fact, you are required to do 4096 refresh cycles each 64ms, and you can do them at once at the end of a 64ms period; which can be accomplished easily using a regular timer interrupt. I don't think the refresh is the main issue here - rather, the requirement to issue the address in two pieces might be the potential bottleneck; together with addressing issues in the '51 itself (do you have a 29bit DPTR? :-) Maybe knowing your target application, more suggestions could be made? Jan Waclawek |
| Topic | Author | Date |
| Large RAM bank | 01/01/70 00:00 | |
| Serial? | 01/01/70 00:00 | |
| Speed | 01/01/70 00:00 | |
| Keil...? | 01/01/70 00:00 | |
| Zylogic ZE5? (nee Triscend E5) | 01/01/70 00:00 | |
| Two choices | 01/01/70 00:00 | |
| Use This Idea | 01/01/70 00:00 | |
| Another CPU? | 01/01/70 00:00 | |
| Try This Idea Too | 01/01/70 00:00 | |
| SDRAM maybe viable | 01/01/70 00:00 | |
| What about pseudo static ram? | 01/01/70 00:00 | |
| pseudosrams are not larger | 01/01/70 00:00 | |
| Jez ? | 01/01/70 00:00 | |
| Didn't search first?! | 01/01/70 00:00 | |
| Just a BIG memory? | 01/01/70 00:00 | |
| More information | 01/01/70 00:00 | |
| 512k ONLY? :-) | 01/01/70 00:00 | |
| attach to large SRAM | 01/01/70 00:00 | |
DS80C400? | 01/01/70 00:00 | |
| I did | 01/01/70 00:00 | |
| SDRAM controller | 01/01/70 00:00 | |
| keep it simple&stupid | 01/01/70 00:00 | |
| suggestions and questions | 01/01/70 00:00 | |
| Thanks for input | 01/01/70 00:00 | |
| 2M=4x512k | 01/01/70 00:00 | |
| Good idea | 01/01/70 00:00 | |
| PCB Space - Above & Below | 01/01/70 00:00 | |
| Have you tried ISSI | 01/01/70 00:00 | |
| CF card | 01/01/70 00:00 | |
| Using SD | 01/01/70 00:00 | |
| CPLD | 01/01/70 00:00 |