Power error in SIM7020G?
-
Hi, i have a sim7020c in my schematic, but when i press pk the serial conection works for 4-5 seconds, then stops and i need press other time, but the sim reset and i can’t make any conection
I connect to vbat a lipo 16850 and the same error
-
Hello @Diego8663
not sure it has to do with the issue you are seeing, but I found some points you might want to check out.
- afaik the 16850 has a nominal voltage of 3.7 V (and a maximum of 4.2 V). According to the SIM7020G datasheet, VBAT has a maximum input voltage of 3.6 V only.
- in your schematic I don’t see any capacitors on the VBAT line. The reference design has five capacitors in parallel (2x 100 uF, 100 nF, 100 pF, 22 pF).
- the UART interface lines are in the 1.8 V domain. Are you using some kind of level shifter (outside the schematic) to connect to your MCU (which most likely is 3.3 V or higher).
- in the reference design the network status LED is connected via a transistor (and not direct as in your schematic).
Thanks
Felix -
@fm thanks fo you answer, i gonna make this changes is my first pcb advanced desing
-
@fm hi, i add a 3.3 regualtor to vbat and add a capacitor
i see this on terminal
*MATREADY: 1 i don’t undestand this
+CFUN: 1
+CPIN: READY
-
Hello @Diego8663
that is a good question. While
*MATREADY: 1is listed as unsolicited result code in the SIM7020 AT document the description column is empty. And searching the Internet doesn’t really help either.That said, my best guess would be that it means something like ‘Module AT READY’ or in other words the module is ready to accept AT commands.
Thanks
Felix