From this page you can set the number of EVMs you are using, and then for each EVM you can indicate the
physical hardware switch settings and configure your shunt and CURRENT_LSB. Below is a description of each
option and field on this page:
• Number of EVMs
– This setting is used to tell the GUI how many EVMs are connected to the SCB.
– Note, the SCB and GUI only support up to 4 EVMs at a time with the same device on each EVM.
– Changing this here also changes the same setting in the Results Data tab.
• Selected EVM
– This setting indicates which EVM you are currently changing settings for.
– This also selects the EVM that is connected to the Registers page.
• Hardware Switch Settings
– Set these settings to match the physical switch settings on the EVM.
– Note, this setting needs to be set before changing any other settings on this page. The GUI will block the
other settings until this is set.
– Changing this here also changes the same setting in the Results Data tab.
• Shunt Full-Scale Differential Range
– This is a shortcut to the ADCRANGE setting from the registers page, placed here for convenience.
– Both this setting and the ADCRANGE setting from the register page change together.
• Shunt/Current Configuration
– This section is used to input shunt information as well as to help calculate the CURRENT_LSB and set the
SHUNT_CAL register. Here is a description of how to use each field:
• RSHUNT
– Input the value of the used shunt resister in mΩ.
• Max Expected Current
– Input the value of the maximum expected current across the shunt resistor in Amps.
– If the Max Expected Current field is left blank, then SHUNT_CAL can be adjusted manually, and the
tool will tell you the True Max Current that can be measured with the EVM.
• CURRENT_LSB
– This is the calculated CURRENT_LSB value in Amps. This field gets populated automatically from
the Max Expected Current field.
– This field can be changed manually if desired, and changes will filter downward.
• SHUNT_CAL
– Calculated value for SHUNT_CAL based off of RSHUNT and CURRENT_LSB. When this field
changes, the value is automatically written to the SHUNT_CAL register.
– When CURRENT_LSB is specified, changing ADCRANGE will adjust this value automatically per
data sheet equations.
• This will happen if ADCRANGE is changed from either the configuration page or the register
map.
• If CURRENT_LSB is not specified, this value will remain unchanged, but the fields below will
adjust to the new ADCRANGE.
– This field can be changed manually if desired, and changes will filter downward.
– Changing this value from the register map page also changes it here.
• True CURRENT_LSB
– This is the actual CURRENT_LSB value in Amps back calculated from the SHUNT_CAL register
with the given shunt resistor value.
– This is the value used for calculations in the Results Data section.
• True Max Current
– This is the maximum measurable current in Amps based off of the VSHUNT and CURRENT
registers, using RSHUNT and the True CURRENT_LSB for calculations.
• Required Sensing Range
– This shows the required sensing range to measure the Max Expected Current with the specified
shunt resistor.
– If a Max Expected Current is not specified, then the True Max Current field will be used instead.
Operation
12
INA228, INA229, INA237, INA238, and INA239 EVM User’s Guide
SBOU241C – APRIL 2020 – REVISED JULY 2021
Copyright © 2021 Texas Instruments Incorporated