| ??? 05/16/09 17:42 Read: times |
#165420 - Check your wiring and voltages Responding to: ???'s previous message |
Makarand said:
1)When I start FM without connecting cable to com port,the usual window of "reset the device"pops up & remain.
But the moment try to connect cable to unpowered 8051 board the unusual message i.e. unable to connect....comes on the screen. One more thing if I remove MAX232 Chip and start FM it waits for resetting the device. And more interestingly when I put MAX232 chip from my older tested board everything works fine. That suggests MAX232 ic is faulty. But I tried out by changing almost dozen Ics. But system works with only with the older Ic. I am confused... It never happenned. 2)My program doesnot write to rs232 port as it works as a slave in modbus environment. 3)My rs 232 port has 3 wires rxd/txd/ground. I can only suggest that you double-check your hardware. MAX232 is supposed to work only for 5V. There are variants for 3V chips. Check the manufacturer and batch numbers. You will have to set your own hardware condition to enter the bootloader. This generally involves PSEN and RESET. The only other thought is that the MODBUS is loading the RX line and consequently your 8051 does not hear or echo the correct stuff back to FM. David. |
| Topic | Author | Date |
| Flash Magic problem | 01/01/70 00:00 | |
| have you tried the FlashMagic forum? | 01/01/70 00:00 | |
| re | 01/01/70 00:00 | |
| Chars in RS232 buffes. | 01/01/70 00:00 | |
| re:David | 01/01/70 00:00 | |
| Does the existing program write to UART ? | 01/01/70 00:00 | |
| re:David/Observations | 01/01/70 00:00 | |
| Check your wiring and voltages | 01/01/70 00:00 | |
| have you perchance .. | 01/01/70 00:00 | |
| Voltage Levels | 01/01/70 00:00 | |
| NEVER ... | 01/01/70 00:00 | |
| RE: NEVER.... | 01/01/70 00:00 | |
also | 01/01/70 00:00 | |
| I've experience these problems | 01/01/70 00:00 | |
| Did you read the FAQ? | 01/01/70 00:00 |