Max5 Power Monitor

[Altera_Forum]

Hello, 

 I'm working with the Arria starter kit. To start with, I've already seen this: http://www.alterawiki.com/wiki/how_to_read_power_monitor_value_in_system_console  but I still have some questions.  1)How do I figure out what the reference voltage is for a given rail? 2)How do I figure out what the resistance is? 3)Where do these numbers comes from? sld_access_ir $vj 1 2 vs. sld_access_ir $vj 2 2  4)The output I get from sld_access_dr $vj 16 1  [list 0x00 0x00] looks like : 0x11 0x0, 0x16 0x0, etc.. is this backwards? I ask because the upper bytes shift wildly between 0x10 and 0x20, and the lower bytes are always 0x0, which seems backwards to me.  Thanks, Jonah

[Altera_Forum]

Hi Jonah, 

 Yes, very likely it is "backwards" (i.e., the least significant byte is printed first).  I am sort of reverse engineering Power Monitor's behavior to automate some measurements on a Cyclone IV Development Kit.  Here are some observations, which may or not be true: - The values read seem to the the least significant bits of a 24-bit ADC; in the formulas, some have advised dividing the reference voltage by 23 and multiplying by the value read. - You can read the resistance values by looking at the components on the PCB, or by looking and the schematics or datasheets for your board. - I believe all rails use the same reference voltage, because it is a single configuration for the whole ADC. In my board, it seems to be 5.37 or 5.0V. - The number changing from 1 to 2 in your question# 3 is the value to be written in the instruction register. The second value should be a timeout in microseconds.  Hope this helps.  Ricardo

[Altera_Forum]

I've created a script to read the current values from a command line, using system-console. It's been tested with the 'Cyclone IV GX Transceiver Starter Kit' and 'Cyclone IV GX FPGA Development Kit' boards, but it should be easy to adapt to other platforms. 

 https://github.com/ricardo-jasinski/power_monitor_automation  Good luck!