Sensirion SHT71 with PIC18F2550
Guest
#1991049
Hi, I'm having problems interfacing a Sensirion SHT71 with a PIC18F2550. I want to measure the humidity and send it via EUSART to the PC, but I get nothing on the PC side. I've used the EUSART several times so that is not the problem. I've attached my assemblerlisting and I hope someone can help me. Thanks in advance, Marius
Guest
#1992598
You should use a scope an check out the communication step by step. Get some Debug-Informations too. I guess you are using MPLAB. So check out the Debug-mode (View->Watch) It's very helpfull. Btw: The error is hard to tell, if you dont name the problem more precisely.
Guest
#1993048
Unfortunately I don't have a scope. It seems like there's a problem with sending a command. On the ACK impulse I can see that the sensor pulls the DATA line low (line 144), but it doesn't pull it high afterwards like it's shown in the datasheet.
Guest
#1993343
my assembler isn't that good. maybe it's a timing problem. try to slow the clock down. but it could be one of many things. you should really use that debugger and check all signals step by step. Reply |