| ??? 02/20/07 04:18 Read: times |
#133278 - 9 volt to 5 volt bidirectional logic interface? |
Hi all...
I have a weird old ROM from the late 70's that I need to read the data off of. Testing in circuit shows that it actually runs at 9 volts and has logic levels of 9 volts. This agrees with an old spec sheet that I found on it. Are there any 8052 derivatives out there that are capable of running natively at 9 volts? (or any other uC's for that matter) Failing that, I have a drawer full of regular 5-volt Atmel 8052s that I could use if anyone has any suggestions for a bidirectional logic level shifter IC that could handle it, or a relatively simple discrete circuit. I thought about using a bunch of MAX232s to do the level shifting, but they're unidirectional. I need to be able to bit bang on some shared address/data lines. There's lots of solutions out there for 5v to 3v, but I can't find much on 5v to 9v. Thanks very much for any suggestions! -Sam |
| Topic | Author | Date |
| 9 volt to 5 volt bidirectional logic interface? | 01/01/70 00:00 | |
| rather than "wierd old ROM" why not part number? | 01/01/70 00:00 | |
| if you need to use a misspelled pseudonym | 01/01/70 00:00 | |
| TI TMS6100 speech synthesis ROM | 01/01/70 00:00 | |
| my bad | 01/01/70 00:00 | |
| NXP bidir level shifter appnote | 01/01/70 00:00 | |
| Easy ROM interface | 01/01/70 00:00 | |
| something similar just occured to me | 01/01/70 00:00 | |
| Current limiting resistors | 01/01/70 00:00 | |
| great, I think I've got it | 01/01/70 00:00 | |
| read the datasheet twice ... | 01/01/70 00:00 | |
| voltage question and datasheet errata | 01/01/70 00:00 | |
| Why Vss is positive and Vdd is negative | 01/01/70 00:00 | |
what I meant was ... | 01/01/70 00:00 | |
| RCA/Intersil micro can do 11V | 01/01/70 00:00 | |
| and there was that 1 bit micro... | 01/01/70 00:00 | |
| device programmer, tester | 01/01/70 00:00 | |
| naw ... just use the old RS232 level shifters | 01/01/70 00:00 |