18F25J50 and PPSTool

[George Towler]

I can't seem to find 18F25J50 in PPSTool, am I missing something or is the device not supported?

BTW I find PPS completely impossible to deal with manually, if 18F25J50 isn't supported by PPSTool, I'll ditch them (although 2 async ports and 4k RAM are very attractive).

[Peter]

George,
I have a feeling that the J chips are not supported however let me check when I get a chance (may be at the weekend). There is a list of known, unsupported chips in the help file.
There has been an update to the XML files by microchip which hasn't been implemented yet. I think it included a few more chips but can't remember which ones.
GeorgeGeorgeGeorgeGeorgeGeorgeGeorgeGeorgeGeorgeGeorgeGeorge

[Anobium]

The 18F25J50 is a very very early implememtation of PPS. Neither PPSTool or MPLAB-IDE/MCC module support this older PPS definition.

Ditch the chip, get a 18fxxK42.

[George Towler]

@Peter thanks in advance for anything you can come up with.

@Anobium Yes K42 is nice but I need the USB support. Unless Peter comes up trumps I'll have to revert to the K50.

[Anobium]

Lots of other parts with USB but I would proceed with K50 or hand crank the PPS on a J50.

Simply test for PPSTool support. If MPLAB-X supports PPS on a part then PPTTool will. I checked the J50 is not supported when I checked yesterday in v5.15 & v5.10 - I could be mistaken but probably not.

Hand crank the PPS on a J50 - you will have fun.

[George Towler]

Sadly my old brain has several mental blocks, Microsoft COM and PPS being several examples.

[Anobium]

Then, the K50 it is then.

[Anobium]

Or, the 16f145x

[Anobium]

or, the J53

[Anobium]

or, any chip and use the software USB solution 16F1.......

[George Towler]

Ohhh, I didn't know about J53. Good find. I must do battle with MAPS to find out what else I missed.

Thanks a million, as they say in this neck of the woods, for the suggestion.

[Anobium]

I did not use MAPS. I just looked in the Great Cow BASIC demo folders. :-)

[George Towler]

Ha f ing ha, just saw the errata for K53, the clock for EUSART tx and rx is derived from different places in the clock gen chain!

[Anobium]

and, that means?

Not sure what the issue is. What capability of the EUART does not work in Great Cow BASIC? I have been using serial on this part for a long time. Maybe something we do not know about.

[George Towler]

From the Errata

The EUSART may transmit and receive at
different baud rates under the following
circumstances:
• a system clock source other than the
Secondary Oscillator has been selected, and
• a CPU clock divider (CPDIV<1:0>,
CONFIG1H<1:0>) other than 1:1 has been
programmed.
This is because the receive baud rate clock
source is generated from a point prior to the
CPU prescaler, while the rest of the logic is
clocked at the system clock frequency (following
the prescaler).

[Anobium]

Not an issue. Use the software Serial library.

[George Towler]

What is the max baud rate for the software serial libruary?

[Anobium]

I looked in the Help.

3 independent channels Ser1…​ , Ser2…​ , Ser3…​
I/O pins user configurable
polarity can be inverted
freely adjustable baud rate
maximum baudrate depends on MCU speed

PIC@ 1Mhz 9600 baud
PIC@ 4Mhz 38400 baud
PIC@ 8Mhz 64000 baud
PIC@16Mhz 128000 baud

Does not have a spec for above 16Mhz but I am thinking a tad faster than 12800

[George Towler]

Wow thats incredible, I've never seen reliable bit bang async faster than about 19200.

How on earth do you acheive that without using interupts and timers?

Is that code in a seperate libruary or part of the core code?

I run Pic device ate either 48 or 64Mhz so I can even imagine what speed it will tx and rx at!

[Anobium]

Standard library. All shown in the demos and Help.

Developed a few years and it works very nicely.