Flash Erase Suspend

RE: Flash Erase Suspend

kerko — Mon, 12 Jun 2023 23:50:07 GMT

Thanks haakonsh.

After a few days of fiddling around I finally get erase suspend/resume working properly.

It works within a sector erase as well.

RE: Flash Erase Suspend

haakonsh — Mon, 05 Jun 2023 12:06:15 GMT

From the MX66L1G45G datasheet chapter 9-41. Erase Suspend:
"If the system issues an Erase Suspend command after the sector erase operation has already begun, the device will not enter Erase-Suspended mode until tESL has elapsed."

Looks like you won't be able to lower power peaks with Erase Suspend unless you are erasing multiple sectors, but then you could also just erase one sector at a time without using the Erase Suspend feature.

As for the difference in current consumption I assume to be attributed to the different operating voltages and sector erase times: ~7mA for 65ms @1.8V vs ~19mA for 30ms @3.3V.

As for mitigating the load peaks with regard to your power supply I think you need to consider adding a small supercap to your power supply.

RE: Flash Erase Suspend

kerko — Mon, 05 Jun 2023 03:11:20 GMT

My apologies haakonsh. I've been taking measurements with our custom board as well as nRF5340-DK board and I messed up the measurement screenshots.

So below is the single page erase power measurement I've taken, using our custom FW on the nRF5340-DK board. The average current is 7.9mA, but the baseline current was around 0.7mA, so if we deduct that, it takes 7.2mA for 65mS to erase 1 page of flash.

We also have our own custom board which uses MX66L1G45G AS THE FLASH CHIP. When I measure the erase page power consumption with the same FW, I get 19.5mA for ~29mS. Screenshot below.

Erase page peak power drawing characteristics are much different to each other. When I check the datasheets of the flash chips, erase currents seems to be same. Is such a difference normal?

Kind Regards,

RE: Flash Erase Suspend

haakonsh — Fri, 02 Jun 2023 17:46:53 GMT

I'm a bit confused as the maximum current consumption of the mx25r64 flash device on the nRF5340 while erasing should be 3.1mA typ and 6mA max. Are you using the on-board mx25r64?

In order to support more flash opcodes you need to expand drivers/flash/spi_nor.c. Se f.ex. spi_nor_cmd_write().