Access to ADC0 differential pair on teensy 3.5

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sig11

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Hi forum,

I have an application, too complex to call a sketch actually, running smoothly on teensy 3.1/2 that gets its input from two ADC differential pairs. Now the need has arisen for a second DAC, but I'm running low on IO pins, so I thought that moving up to teensy 3.5/6 might solve the problem. But on studying the pin-out I noticed that there seems to be no way to connect ADC0 to a differential pair.

For teensy 3.5 I see the following:
ADC0_DP1 on pin J1 brought out to A25
ADC0_DM1 on pin J2 seems to be not connected?
ADC0_DP0 on pin L1 brought out to USB1_VBUS pad & connected pin G2 VREG_IN0 - nsg
ADC0_DM0 on pin L2 seems also to be not connected?
ADC0_DP3 on pin M1 brought out as A10 and used by ADC1_DP0
ADC0_DM3 on pin M2 brought out as A11 and used by ADC1_DM0
The last two pins look great for interleaving the two ADCs, albeit that's not what I'm after, and there seems to be no way to move ADC1 elsewhere.

I did not investigate teensy 3.6 in depth, but it seems hopeless with the second USB port.

Any deeper insight would be much appreciated, in the hope that I missed something.

Thanks,
Carsten
 
T_3.5 has A26 where the T_3.6 uses that pin for USB the T_3.5 doesn't have. A25 is noted in code as (no diff) - but it is there too for T_3.5.

From Arduino : A sketch is the name that Arduino uses for a program. It's the unit of code that is uploaded to and run on an Arduino board.

Amazing how large the dozen or so phone apps that get updates each week - 5-50 MB+
 
Thanks defragster, for the prompt reply. According to the schematic pin A26 is connected to pin K1 which can only be mapped to ADC1_DP1, but ADC1_DP1 appears only on K2 which seems to be nc. So no luck there.
Without wanting to get into a linguistic discussion, I find some of those phone apps are indeed rather sketchy.
 
Unfortunately, there just isn't any way to get the 2 diff pair analog input. Some of those pins just aren't brought out from underneath the BGA. With 144 BGA pins and "only" about 64 I/O signals able to come out, and a single PCB for K64 & K66 where USB host was an essential feature, trade-offs & decisions had to be made. Multiple differential analog didn't make the cut. :(
 
Thanks Paul, I already figured as much. I appreciate your design decisions, catering to a tiny minority, like myself, would have entailed the need for separate boards for K64 and K66. Anyhow, the K20/teensy3.2 remains the better choice for my project, especially since I found out that by moving a few things around and maybe desoldering the LED I'd be able to open a 12bit PP on PortC. Brilliant design right there! Still testing an analog "workaround" for the time being.
 
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