USB Secure DFU speed

RE: USB Secure DFU speed

bjorn-spockeli — Wed, 04 Jul 2018 11:51:42 GMT

Hi Anantha,

I discussed this with the developers that developed the SDK v15.0.0 bootloaders and according to them we've spent significant efforts on optimizing the SDK v15.0.0 bootloaders in terms of throughput, both with the BLE and serial transport layers. Hence, there are not that many knobs left to tinker with to increase the throughput with the current bootloader design.

Best regards

Bjørn

RE: USB Secure DFU speed

Anantha Keshava — Tue, 03 Jul 2018 18:09:21 GMT

Thanks bjorn-spockeli.

Are there any protocol level delays for subsequent commands/data sent to the BL during DFU? Are there any steps to follow to reduce the time to perform DFU on a given medium of transfer?

RE: USB Secure DFU speed

bjorn-spockeli — Mon, 02 Jul 2018 14:56:45 GMT

HI Anantha,

I apologize for the late reply. As my colleague Kenneth has written, the low throughput is related to the DFU protocol and flash write/erase times, not the USB peripheral. I will see if I can dig up some performance numbers for our serial bootloader. The flash write/erase duration can be found in the NVMC's Electrical specification section.

Bjørn

RE: USB Secure DFU speed

Anantha Keshava — Wed, 27 Jun 2018 16:33:24 GMT

Hi Kenneth, Thanks for your response.

Are there any known numbers for these operations in terms of duration for performing a page of erase, write, verify etc? This will be extremely helpful in evaluation of platforms and manufacturing plans.

RE: USB Secure DFU speed

Kenneth — Wed, 27 Jun 2018 11:31:11 GMT

The main limitation here is likely the flash erase, write and verify operation, the CPU is halted during these operations, thereby 115200 is the max baud you should use.