| ??? 06/10/11 05:32 Read: times |
#182567 - i'm confused by AT89S52 Responding to: ???'s previous message |
in Atmel document i read
http://www.atmel.com/dyn/resources/prod_documents/doc1919.pdf on page 6: Atmel said:
4.10 EA/VPP External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. I cant be sure that AT89S52 will work in way, described by You (and i believed is standard until now). regards |
| Topic | Author | Date |
| Bootloading using external RAM and EA switching? | 01/01/70 00:00 | |
| Not sufficient! | 01/01/70 00:00 | |
| Use single SRAM chip by tying PSEN to RD? | 01/01/70 00:00 | |
| That qualifies as... | 01/01/70 00:00 | |
| Experimentation ;) | 01/01/70 00:00 | |
| No need for experimentation | 01/01/70 00:00 | |
| Fast-forward to 2010 or thereabouts | 01/01/70 00:00 | |
| It would be a pretty narrow window, but ... | 01/01/70 00:00 | |
| methinks the real reason | 01/01/70 00:00 | |
| That's true for program updates, but ... | 01/01/70 00:00 | |
| visualizing any case where the regular ISP/IAP is too slow | 01/01/70 00:00 | |
| ... and FRAM's pretty fast, too ... | 01/01/70 00:00 | |
Would have liked to have used FRAM... | 01/01/70 00:00 | |
| As long as intervening RESET | 01/01/70 00:00 | |
| do You need EA controlled? | 01/01/70 00:00 | |
| hmm | 01/01/70 00:00 | |
| not surprised | 01/01/70 00:00 | |
| Decided not to use EA (rather, shouldn't) | 01/01/70 00:00 | |
| i'm confused by AT89S52 | 01/01/70 00:00 | |
| This is the page I found | 01/01/70 00:00 | |
| great | 01/01/70 00:00 |