| ??? 11/21/11 10:15 Modified: 11/21/11 10:18 Read: times |
#184842 - external execution in '41/'42 Responding to: ???'s previous message |
Richard Erlacher said:
Those 8041/8042 chips are hard-coded ROM-based chips, hence won't do much, as, IIRC, they don't work with external memory. UPI-41A/41AH/42/42AH USER'S MANUAL said:
EXTERNAL ACCESS The UPI family has an External Access mode (EA) which puts the processor into a test mode. This mode allows the user to disable the internal program memory and execute from external memory. External Access mode is useful in testing because it allows the user to test the processor’s functions directly. It is only useful for testing since this mode uses D0–D7, PORTS 10-17 and PORTS 20–22. The rest of this chapter goes on with details how to demultiplex the port values (including the data "exchange" port) from the external memory access. In this aspect, it appears to be quite similar to the external execution of 8048 (or 8035, if you want). I admit it is not trivial, but appears doable. Unfortunately, I don't have the time to prove it. JW |
| Topic | Author | Date |
| Sourcing historic uCs | 01/01/70 00:00 | |
| Vintage MCUs | 01/01/70 00:00 | |
| 8041 | 01/01/70 00:00 | |
| Unfortunately ... | 01/01/70 00:00 | |
| external execution in '41/'42 | 01/01/70 00:00 | |
| I don't doubt what you said ... | 01/01/70 00:00 | |
| Have some old 8748, 8749 and V20 chips | 01/01/70 00:00 | |
| I've got some other old MCU and MPU chips ... | 01/01/70 00:00 | |
| Can you program them | 01/01/70 00:00 | |
| Some of us have those ... even the programmables | 01/01/70 00:00 | |
| If I can find 'em ... | 01/01/70 00:00 | |
seems still live | 01/01/70 00:00 |