Hi There
I have GPS module TTL output connected to my Netduino Mini. I connected(Tx) from GPS to pin 12 of Mini (Rx) .
On my oscilloscope I measure data received at +2vdc level to GND .
The mini does not accept the data as valid.
I tried pull up resistor and LEDs on Rx of Mini line but no change.
I tested the output of GPS with MAS232 to PC serial port I get good results ( as expected )
Any idea what is going on ?
Kind regards
Nissim
UART voltage level
Started by Nissim, Oct 17 2011 12:29 AM
3 replies to this topic
#1
Posted 17 October 2011 - 12:29 AM
#2
Posted 17 October 2011 - 12:44 AM
Hi Nissim,
If the GPS is only outputting 2V instead of 3.3V, the voltage may not be strong enough to register with the Netduino.
According to page 610 of the microcontroller datasheet, a voltage of exactly 2.0 volts will register as "high" on the SAM7X MCU. ~2V may not be strong enough.
http://www.atmel.com...nts/doc6120.pdf
If you deploy/debug via TTL (pins 11/12) and hook the GPS up to the RS232 com port (pins 1/2) using your MAX232 circuit...does that work for you?
Chris
#3
Posted 17 October 2011 - 04:11 AM
Thank you Chris
I tested the very same code with Netduino Plus and I get good results
I changed one line for Netduino Mini
using SecretLabs.NETMF.Hardware.NetduinoMini;
and I do not get same results as with Netduino plus
I am wondering about deploy/debug via pins 1/2 which I am using for testing after deployment is successful.
I can not see how to deploy to pins 11/12 TTL level- do I need extra hardware MAX232 ?
Many thanks
#4
Posted 21 October 2011 - 11:14 PM
All problems related to receiving data from uart solved once I have downloaded the latest ER_CONFIG and ER_FLASH.
To save yourself hours of mucking around debugging your own code - download latest files to override default original files supplied with min.
cheers
Nissim
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