HUAWEI GPS Module - Page 1
Forum section: electronics / projects

author: mojoe
author_rank: Frequent Contributor
timestamp: March 02, 2024, 06:53:32 pm
content: There are several vendors selling these boards on ebay. I bought a couple of the LEA-M8T variety. There are also 5T and 6T versions for less money.I'm waiting for the SMB-SMA adapters that I ordered to arrive, so I haven't powered up the boards yet. However, I did figure out one thing about antenna power that I thought I'd share.The 8-pin header on the end of the board is 2 mm (I also had to order some 2 mm dupont cables). Pin 1 is clearly marked. The pinout is:1 - Ant power2 - Vcc (3.3 V for the GPS module)3 - TX4 - NC5 - RX6 - PPS7 - NC8 - GndThe antenna power on pin-1 is there so that you can power an active antenna separately, if it doesn't use 3.3 V. If you are using a passive antenna, leave pin-1 unconnected. If your antenna does take 3.3 V, and you want to power it via the bias tee in the GPS module, without needing to put 3.3 V on both pins 1 & 2, jumper the two solder pads next to the 10 Ohm resistor (see the picture). This will place the 10 Ohm resistor across pins 18 & 19 on the GPS module, powering the antenna via the internal bias tee. Of course, if you do this, don't apply voltage to pin-1.

author: mojoe
author_rank: Frequent Contributor
timestamp: March 06, 2024, 03:08:30 am
content: I received the SMB-SMA adapters and 2 mm Dupont cables this evening. I hooked up the first module to a USB-TTL serial adapter, set for 3.3 V. At the moment, I'm powering the active antenna separately from the same 3.3 V. Later, I may short the jumper on the board, depending on what antenna I eventually use.Here in my living room (first floor), it got a 3D fix and was tracking nine satellites in less than a minute. The M8T seems more sensitive than the M6T that I have.The configuration looks like the defaults for an M8T. GPS, GLO BDS & QZSS were enabled. I disabled all but GPS. It's already set to Stationary, which I believe is the default for a timing module.The PPS works, but there is no LED on the board. The PPS is changeable, as it should be.Edit: the firmware is 3.01, protocol 22.00, TIM 1.01 running from flash. The ROM has firmware 2.01.As you can see, the antenna I'm using for testing is nothing special, just a patch antenna sitting on a mesh splatter screen, on the seat of my ebike.

author: mianos
author_rank: Regular Contributor
timestamp: March 18, 2024, 04:45:25 am
content: I just got one of these, same. Got an SMB to SMA adapter from the fleabay too. SMB is a nice connector with a solid 'clunk' when connecting them.areThere are a few other threads on these.I am using it for my esp32 GPSDO. I have an mqtt command that does a serial passthrough from the esp serial port to the serial pins it's connected to.I am running ublox on wine for MAC. Kinda amusing to be talking 110K baud to the LEA-m8T port at 9600. The ublox and pygps software does not seem know so my code is OK. I'm going to insert the ocxo control and measurement parameters into the normal NMEA stream.These GPSs have a special mode where, if they are static and there is enough signal they will switch into a precision timing mode.I am only seeing 30dBHz signals through the ceiling so mine does not seem to switch yet. I'll have to finish the code to detect this and put the antenna outside.I just ran the 3V to the active antenna power from the same as the other supply.