| ??? 01/14/05 18:09 Read: times |
#84993 - need help on serial communication |
Hi, I am doing a project requiring the ATmel 89s51 microcontroller to send signals to the serial port of my PC through the MAX232. I have setup everything and once there's an input from either one of the P0.0, P0.1 or P0.2 pins of the 89s51, it will send a character A via the RxD pin to the MAX232's T1 IN and then sent to the serial port. I connected the MAX232 using the DB9 female cable with pin 3 to the MAX232's T1 OUT and pin 5 to ground but I can't seem to get any signal while testing it with an oscilloscope. Can anyone help?
this is the code for the 89s51: ORG 0000H LOOP1: JNB P0.2, LOOP2 SETB P1.0 CALL SERIAL LOOP2: JNB P0.0, LOOP3 SETB P1.1 CALL SERIAL LOOP3: JNB P0.1, LOOP1 SETB P1.2 CALL SERIAL SERIAL: MOV TMOD, #20H MOV TH1, #-3 MOV SCON, #50H SETB TR1 CLR TI MOV SBUF, #'A' JNB TI, $ RET Thanks a lot |
| Topic | Author | Date |
| need help on serial communication | 01/01/70 00:00 | |
| Your setup | 01/01/70 00:00 | |
| simulator testing | 01/01/70 00:00 | |
| read eall about it | 01/01/70 00:00 | |
| Hardware | 01/01/70 00:00 | |
| Why the MAX232 | 01/01/70 00:00 | |
| Yes :) you right Steve. | 01/01/70 00:00 | |
| Handshaking? | 01/01/70 00:00 | |
| One step at a time | 01/01/70 00:00 | |
| setup correct? | 01/01/70 00:00 | |
| connector pinouts | 01/01/70 00:00 | |
| Schematic | 01/01/70 00:00 | |
| help again sorry | 01/01/70 00:00 | |
| easy | 01/01/70 00:00 | |
| Exclude trivial problems | 01/01/70 00:00 | |
| code for sending a character | 01/01/70 00:00 | |
loop back handshaking | 01/01/70 00:00 |