| ??? 04/18/05 12:12 Read: times |
#91815 - why and how Responding to: ???'s previous message |
I have a 8051 which runs on 5V DC powersupply.
I need to interface it to FPGA which has 3.3V supply. 1) There are (still) many 5V CPLD/FPAGs around why not use one of those OR use s 3.3V uC (e.g. Philips LPC or Silabs). This will save you the cost of a bottle of aspirin and a lot of interface components. 2) If you absolutely have to do this (because you happen to have the 2 chips and want to save $5 id NOT a valid reason) the following is the only surefire way to interface 3.3V with 5V: for 5V to 3.3V (or bidirectional) use a chip lile the 74LVC4245. for 3.3V to 5V use the above or 74HCT chips as interface. The "open drain and resistor" method may, indeed, work, but who whants to discover after several months that there is a noise problem because of narrowed noise immunity. Erik |
| Topic | Author | Date |
| FPGA 8051 | 01/01/70 00:00 | |
| Level translator | 01/01/70 00:00 | |
| 5V and 3.3V | 01/01/70 00:00 | |
| Read this | 01/01/70 00:00 | |
| Something else to read | 01/01/70 00:00 | |
| why and how | 01/01/70 00:00 | |
| How true,,,,,Or | 01/01/70 00:00 | |
| Surface mount :( I need DIP | 01/01/70 00:00 | |
| FPGA on perfboard?! | 01/01/70 00:00 | |
| 8051 + FPGA + OV6620 Camera | 01/01/70 00:00 | |
| My cat says....... | 01/01/70 00:00 | |
| Doh! | 01/01/70 00:00 | |
| as Andy said | 01/01/70 00:00 | |
| 8051 + FPGA + OV6620 Camera | 01/01/70 00:00 | |
| Which still begs the question.. | 01/01/70 00:00 | |
| ... and another question | 01/01/70 00:00 | |
I would | 01/01/70 00:00 | |
| I thought | 01/01/70 00:00 |