Logomatic v1.0

Archive SparkFun Site Questions/Comments
1

Hi everybody!

I am trying to connect one GPS to Logomatic v1.0. GPS’s UART is working on RS232 and when I connecting like that on Logomatic I have garbage in datafiles. When I am trying to connect it with TTL levels I don’t have anything in datafiles!

Please help! :shock:

2

Is it, maybe, reason of my problem that I am using MAX232 instead MAX3232? :oops:

3

I had solved my problem with using MAX3232!

Now I am interesting is there some chip that converting logical signals of chips that are working on 5V to logical signals for chip that are working on 3V?

Also, one more question. When I am using mode “1” for logging I can’t use text frame smaller than “100”. Does somebody knows why?

4

You could just use a resistor divider for that . A 1k series and 2k to ground should work.

        1K
5v ---->-<-----3.3v
           |
           v
           | 2k
           ^
           |
          GND
5

Is that for both lines (RxD and TxD)?

6

That circuit works for 5V output to 3.3v input. For 3.3v output to 5v input, you need to check your 5V part to see what input logic levels it needs. Some 5v parts are TTL compatible which means at least 2V for an input high, which should work with a 3.3v CMOS device putting out 3V+.

7

Thanks!

I will try it :wink: