palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 03:11am 20 Sep 2023
MM V5.05.05 throws an error if INV is used with the OPEN command. From the manual pg. 85 . I suspect it is an obsolete command and has been inadvertently left in the manual. Edited 2023-09-20 13:12 by palcal"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 5962
Posted: 03:27am 20 Sep 2023
I think that INV was only relevant where the hardware supported it.
Jim
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 03:32am 20 Sep 2023
I have a VK2828U7G5LF that works OK with a Micromite, I also have a VK2828U8G5LF, thats with a U8 not U7 it will not work with the Micromite but works OK with a Picomite using the GPS function. What's the difference.
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6027
Posted: 06:41am 20 Sep 2023
INV is usually an option on a "proper" UART or USART but not on a "serial communications module" or whatever they like to call it. If something has a true UART or USART module built in then it may well be supported. If it's only a simulated UART then it may not. What it does, of course, is to allow TXD and/or RXD to be inverted so that they can be connected to inverting line drivers and/or receivers.
phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1911
Posted: 07:58am 20 Sep 2023
If memory serves, the PIC32 hardware serial ports can use the INV option to allow connection to RS232 gear using just rudimentary level conversion. Often just a resistor in the MM2 RX line. I have used it in the past when connected to a laptop for the console. Perhaps INV is only available on COM1:
If your modules work on a Pico then they must be TTL serial and don't require inversion.
Edit INV should also be available on COM2: but not on any "Embedded C Module" ports. Edited 2023-09-20 18:06 by phil99
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 08:24am 20 Sep 2023
Yes INV is only available on COM1: and I am using COM2:, which explains the error. I will try COM1: with INV and the GPS module that did not work on COM2: and see if it works.
phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1911
Posted: 08:37am 20 Sep 2023
Just tested a MM2 and INV does not throw an error on COM2 if you do it like this:-
> OPEN "COM2:9600",inv as #2 >
The manual shows it should be like this OPEN "COM2:9600, INV" AS #2 but that gives:- Error : COM specification
Have not tested for actual inversion yet.
Edit
Now I see it in the manual, COM1 only! Edited 2023-09-20 18:54 by phil99
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 01:03am 22 Sep 2023
OK I finally got this sorted the VK2828U8 version did not work because the sentence we have to look for is not GPRMC but GNRMC
phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1911
Posted: 01:17am 22 Sep 2023
the sentence we have to look for is not GPRMC but GNRMC
Good to know. Will have to update my old MM+ and MM2 programs.
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 01:20am 22 Sep 2023
Well not yet, I just unplugged from my computer and put on a 5v charger and it has stopped working. I'll look some more but getting close to giving up. I have one of these U8 versions working OK with Geoff's GPS tracker ???
palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1828
Posted: 01:57am 22 Sep 2023
I'll give up on this, it works sometimes and not others, maybe a problem with the module. Edit... still don't understand why it runs on a Picomite OK. Edited 2023-09-22 12:40 by palcal