Trouble with some FT812 based modules & PIC32

[lpmsr]

I am using FT810 with FTDI VM810C "credit card module", which uses the FT810. I am trying to get my program to work with either the Riverdi or 4D modules which use FT812. I can't seem to get either to work with the settings in MB Pro / VTFT that I use for the FT810 board. Any thoughts? I am using mikroBasic PRO for PIC32, but I thought I would also post this to the mikroC PRO group to see if there are users here who have successfully interfaced to any of these FT812 based modules...

Riverdi
4D
Matrix Orbital
Crystalfontz

I have not tried Newhaven who also make these modules because they are higher cost, but I may try them just to see if I can get them to work. There are subtle differences in these modules, but nothing major aa far as I can tell.

I have successfully interfaced to FTDI/Bridgetek brand dev boards which use FT810, FT812 or BT816 EVE chips. For some reason I can't get the other brands to work. I have checked signal polarity and levels, basic timing on a scope, etc., and no luck so far. I must be missing something.

Larry