What is the difference between various TPM modules?
TPM/FW3.19 is TPM 1.2 compatible and TPM-L R2.0 is 2.0 compatible.
Ok, let me explain again. TPM/FW3.19 (20 pins) is an old module created for old Motherboards like P8B, P9D etc. and it's TPM 1.2 compatible. Asus TPM-L R2.0 20 pin replaces TPM/FW3.19 and is for newer MB like X99-based and it supports TPM 2.0. The last one, ASUS TPM-M R2.0 is for Skylake or later motherboards and it supports TMP 2.0. If you have an old MB with 20-1 connector probably Asus TPM-L R2.0 20 pin will not be compatible with it, it depends on BIOS. You have to check it with your vendor. I guess you understand that you can't use 14 pin module on 20 pin motherboard or vice versa.
The naming of pluggables TPM-cards should be something like TPM-L-R2.0, where the L stands for the pins and it's spacing and the R for the protocoll revision.
Please note that on the mechnical part there at least 3 different types. See as well for the electrical part: LowPinCount-Bus (LPC bus).
- pincount (14pins for M, 19 out of 20 pins for L, 17 out of 18 pins for S)
- pinspacing: 2,54mm for TPM-L and 2mm for TPM-S.
TPM-S has the "ident-pin" (the "missing one/stuffed hole") on 3rd last column, TPM-L has the ident pin on the 2nd last column.