| ??? 01/14/07 00:07 Read: times |
#130782 - Level translation Responding to: ???'s previous message |
If the AT89C55WD is running on 5V - then thats what it will output. The AT89C55WD will most likely accept the 3.3V signal from the BT device as being cmos the logic transition level is around 1/2 VCC (~2.5V). That solves one of your signals, the Txd from the AT89W55D is the next problem - yes you can use a resistive divider, but be aware of capacitance effects at higher speeds. At normal serial baud rates, this will likely not be a problem. There are also devices specifically for doing the level translation. |
| Topic | Author | Date |
| AT89C55WD UART voltages. | 01/01/70 00:00 | |
| Level translation | 01/01/70 00:00 | |
| Thanks for that. | 01/01/70 00:00 | |
| Real? | 01/01/70 00:00 | |
| Real | 01/01/70 00:00 | |
| Reak! | 01/01/70 00:00 | |
| Voltage. | 01/01/70 00:00 | |
| Pins | 01/01/70 00:00 | |
| Pins | 01/01/70 00:00 | |
| the peculiar port structure of '51 | 01/01/70 00:00 | |
| The Socket | 01/01/70 00:00 | |
| Socket | 01/01/70 00:00 | |
| HW issues | 01/01/70 00:00 | |
| I am on the road, but someone can verify | 01/01/70 00:00 | |
| SN74LVC4245A | 01/01/70 00:00 | |
| 5V->3V conversion and vice versa | 01/01/70 00:00 | |
| If this is CMOS | 01/01/70 00:00 | |
| No insistance. | 01/01/70 00:00 | |
a link would be nice | 01/01/70 00:00 | |
| PLCC44 | 01/01/70 00:00 | |
| why AT89C55WD? | 01/01/70 00:00 | |
| Read the thread! | 01/01/70 00:00 | |
| AT89LV55? | 01/01/70 00:00 | |
| What is the blue tooth module? | 01/01/70 00:00 | |
| Module | 01/01/70 00:00 | |
| modules | 01/01/70 00:00 | |
| Modules | 01/01/70 00:00 |