 So my ammeter is now connected to my board if I now reset my board using the black button on the front of the evaluation board My current consumption on my meter is about 14.7 milliamps While it's ruined the core mark and then once it's completed the core mark it drops down to about 13.8 Milliamps, so hopefully you should be seeing a similar response. So if we compare that to our Presentation slide that we had So so there we go 14.3 milliamps with the device running at 80 megahertz So we're getting the correct current consumption which works out to be about a hundred and seventy eight microamps per megahertz We're consuming in full run mode so if we now launch our terminal program and We will be able to see the results that we get from the terminal program I will go and launch termites Here is our termite program our configuration for termites needs to be 115 200 bits per second eight n and one change my settings Do one one five hundred eight no and one Okay that Now when I reset my board we now get the results coming from the virtual comport and I am getting 263 iterations per second there from my termite program Which is what I am expecting to see so 263 7 9 6 3 9 2 so I go and look at my termites. Yeah, so not quite exactly 263 0 5 so again slightly different You will get some tiny differences and Between the exact iterations per second But you can see there that we're running from main flash. So 800,000 is the flash Our data is stored in the SRAM. So that's 2 million hex as a start address So our art accelerator is on and we're running at 80 megahertz for this particular cycle So this is giving you the feedback over the virtual comport Back to your PC from the STM 32 L for using the printf statements that we have inside the application So if I now go and change my clock source down to the 24 megahertz So I'll go back into my Code again, so I should now end up seeing about 4.5 milliamps on my Ami to when I run this second exercise I will go in and comment out that line F7 again to rebuild the application Built and if I now go to project Download download active application That's now put my Application back into my board if I now press my reset button on my device I am pulling about 4.8 milliamps on my meter while I'm processing the Coremark score and then that now drops down to about 4.5 when it's finished the results So if we compare that to What we have on the PowerPoint So 4.5 so 4.8 4.5. It's Pretty close there to the numbers and we should see a coremark score on our termites Outputs of about 80.5. Let's go and have a look at our termite example and This one I'm getting slightly less on my board. I'm getting about 78 so so you can see now that Still running out of main flash still in the RAM, but my clock speed is now at 24 megahertz And because of that, I will get a lower coremark score so 78.79 is the coremark score So the next mode we have is low power run mode so This is where the main regulator is now switched off Which means we are now limiting our maximum speed to two megahertz Which is all we can get out of the low power regulator Again on the left hand side USB is the only peripheral that's not clocked. We haven't got 48 megahertz But all the other peripherals are available in low power run mode. So we have the ability to run any other peripheral Even though we're limiting the core speed to two megahertz in this device So here's an overview of the power Consumption versus the frequency. So it's being split into the different run ranges So so we've got run range number one Over the on the right hand side So you can see that Running from flash or SRAM 1 and 2 are all pretty much the same Only when you switch off the ART accelerator. Do you see a Increasing current consumption. So really you do not want to switch off the ART accelerator You leave that because it will provide you with the best output and you can see that we can average about a hundred and thirty to a hundred and forty microamps per megahertz Running at the 80 megahertz point of the device Then same in run range number two Always keep your ART accelerator for the flash so it's done helps with the current consumption and Here your maximum speed is 26 megahertz and again all the three lines running from flash or running from SRAM Pretty close to each other and we can get down near enough to the hundred about a hundred and ten. I think running from the flash Was what we were saying At that particular run range number two Then down in the low power run you can see there's a bit more of a significant difference So that remember the technology is optimized for the 26 megahertz area So even at 2 megahertz. We're still doing very well, but as you slow the device down Then you will see an increase in current consumptions so the best idea for running the device is run it in One of the optimal speeds so 2 megahertz 26 megahertz or anywhere in the run range number one so any speed in run range number one and Process the information as fast as you can put the device properly into sleep modes So use the sleep modes that we have Available on the device rather than just running the device at really really low frequencies So the technology was never designed for that so To make sure that if you have a low power application Try and optimize the application to run at certain frequencies so next I'll have a look at Example number two so low power run This example is Based around a data acquisition logger so so we're doing a Sensor hub where we're just logging data Into the system so we will read the ADC every millisecond from the temperature sensor and Then the data will be sent Over a buffer and displayed on the LCD segment display So this one is example number two so to underscore low power run from RAM and We're now going to run the clock at the two megahertz and We will execute from s-ram one in this example so to Boot the device from s-ram we will need to use the sd-link utility to configure the device and So we will need to use our sd-link utility tool and Set the option bytes So that we are booting from s-ram and not from main flash We will then need to use something to configure The boot zero pin so we will need to put a jumper on the boot zero pin To pull this pin high so to enter boot from s-ram Then boot zero needs to be pulled high When we program the code in We will need to change the start address To be the start of the s-ram so that's two million hex that we need to put into that part of the Configuration tool so when we load our example through sd-link utility we need to do that so what we should see on the display is The current temperature And now warm as rumors we'll see hopefully probably 20 it's fairly warm in here and If we used a Current consumption profiling tool you would see something example that looks like that But we would hopefully get an average current of about 410 microamps we should hopefully see on the ammeter