[Gnuk-users] Gnuk on a faster MCU
gniibe at fsij.org
Mon Sep 11 23:06:44 UTC 2017
Another thing you can try for RSA is that...
If it has more RAM, you can change the line in
size_t wsize = ( i > 1024 ) ? 4 : /* Because of not enough memory. */
to, say, 6 (or 5 if not more).
If still not fast enough, I'd suggest to find a chip with 120MHz.
Yesterday, I checked NXP and found Kinetis/Freescale K22F @ 120MHz.
MK22FN128CAH12 - Kinetis K 32-bit MCU, ARM Cortex-M4 core, 128KB Flash, 120MHz, USB, WLCSP 64
MK22FN256CAH12 - Kinetis K 32-bit MCU, ARM Cortex-M4 core, 256KB Flash, 120MHz, USB, WLCSP 64
MK22FN256CAP12 - Kinetis K 32-bit, ARM Cortex-M4 core, 256KB Flash, 120MHz, USB, 80WLCSP
MK22FN256VMP12 - Kinetis K22: 120MHz Cortex-M4F Performance MCU, 256KB Flash, 48KB SRAM, Full-Speed USB, 64-MAPBGA
MK22FN512CAP12 - Kinetis K 32-bit MCU, ARM Cortex-M4 core, 512KB Flash, 120MHz, USB, WLCSP 80
MK22FN512CBP12 - Kinetis K 32-bit, ARM Cortex-M4 core, 512KB Flash, 120MHz, USB, Thin 80WLCSP
MK22FN512VMP12 - Kinetis K22: 120MHz Cortex-M4F Performance MCU, 512KB Flash, 128KB SRAM, Full-Speed USB, 64-MAPBGA
It includes a regulator (from USB Vbus +5V) and can run without crystal
(no capacitive sensor, just like the chip of FS-BB48).
0.5mm pitch MAPBGA is easier for PCB design/manufacturing/assembly. And
I think availability of the part is better (than other WLCSP ones). But
thickness is 1.23mm. I think that it's not acceptable for the PCB
design which uses bottom layer to put a MCU (like the design of Tomu).
For thin WLCSP 80, thickness is 0.34mm. Since pitch is 0.4mm, it
requires more for PCB design/manufacturing/assembly.
For me, WLCSP would be too challenging, for now. I would consider
something like FS-BB120.
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