| ??? 04/04/07 14:07 Read: times |
#136589 - an answer Responding to: ???'s previous message |
if EA is tied to ground, external memory would always be accessed, at least in the intel's 80C51-BH.
if EA was tied to VCC, and your chip supports internal code memory, and the address you are using with MOVC is low enough, then internal memory will be read. What chip are you using? If you want to use MOVX to read external code memory, then you need to make sure the RD line on the micro is connected to the read enable pin on the external code memory device (usually EEPROM). The read enable pin on many EEPROM's is the OE pin. |
| Topic | Author | Date |
| MOVC question | 01/01/70 00:00 | |
| what derivative? | 01/01/70 00:00 | |
| Re: MOVC question | 01/01/70 00:00 | |
| MOVC is external with /EA low | 01/01/70 00:00 | |
| Eureka! | 01/01/70 00:00 | |
| You are correct | 01/01/70 00:00 | |
| Derivative dependent | 01/01/70 00:00 | |
| I'm a classical sort of guy | 01/01/70 00:00 | |
| I think it is irrelevant to discuss derivatives... | 01/01/70 00:00 | |
| not discussing such | 01/01/70 00:00 | |
| for example DS89C4x0? | 01/01/70 00:00 | |
| yup | 01/01/70 00:00 | |
| Blast from the past | 01/01/70 00:00 | |
| this is how it works with an unlocked AT89C52 | 01/01/70 00:00 | |
| Nice work | 01/01/70 00:00 | |
miniLA | 01/01/70 00:00 | |
| an answer | 01/01/70 00:00 |