treii28
Posts: 77
Joined: Fri May 10, 2013 4:52 pm

2v8 logic?

Tue Apr 25, 2017 2:28 am

I have one of these: https://www.sainsmart.com/sim900-gprs-g ... y-new.html and I'm trying to figure out if the '2v8 logic' is something that can be connected directly to gpio pins or if it's going to damage my pi and/or not be readable logic wise? If I need an interface between, what do I need?

SW

User avatar
FTrevorGowen
Forum Moderator
Forum Moderator
Posts: 4527
Joined: Mon Mar 04, 2013 6:12 pm
Location: Bristol, U.K.
Contact: Website

Re: 2v8 logic?

Tue Apr 25, 2017 2:53 pm

Having followed your link and given that the module appears to use a "serial link" (ie.TxD, RxD) the reference to "2V8 logic" may be a "red herring". You probably need to determine what the voltage levels are on those pins - they could be 2V8, 3V3, or, most likely (given also that the module is powered by 5V) 5V which is not directly compatible with the Pi's (3V3) serial GPIO's.
Trev.
Still running Raspbian Jessie on some older Pi's (an A, B1, B2, B+, P2B, 3xP0, P0W) but Stretch on my P3B+, P3B, B+, A+ and a B2. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm

corporatejoe
Posts: 1
Joined: Fri Jun 29, 2018 3:25 am

Re: 2v8 logic?

Fri Jun 29, 2018 3:46 am

treii28 wrote:
Tue Apr 25, 2017 2:28 am
I have one of these: https://www.sainsmart.com/sim900-gprs-g ... y-new.html and I'm trying to figure out if the '2v8 logic' is something that can be connected directly to gpio pins or if it's going to damage my pi and/or not be readable logic wise? If I need an interface between, what do I need?

SW
Have you gotten any further with this project? I have a sim900 module that was dirt cheap when RadioShack was closing it's doors. http://wiki.seeedstudio.com/GPRS_Shield_v1.0/ It's been sitting for years and I'm just now looking at putting it to use with a PI zero. I'm assuming that the 3.3 logic from the PI will work fine with the 2.8 logic on the Sim900?

Mine has a slightly different board layout and it looks like I need to solder to access the 2.8 UART.

Joe-

User avatar
Z80 Refugee
Posts: 358
Joined: Sun Feb 09, 2014 1:53 pm

Re: 2v8 logic?

Fri Jun 29, 2018 9:57 am

It says that's for Arduino. Arduino uses 5V logic. I don't know what the 2.8 refers to, but you will need to determine exactly what the interface is doing before you can work out how to adapt it.
Military and Automotive Electronics Design Engineer (retired)

For the best service: make your thread title properly descriptive, and put all relevant details in the first post (including links - don't make us search)!

Return to “Add-ons”

Who is online

Users browsing this forum: No registered users and 3 guests