INA229: INA229 Current Register

Hangjie Wang

Part Number: INA229
Other Parts Discussed in Thread: SYSCONFIG

Hi expert,

I would like to confirm with you that if the Current Regisiter reading is 0F FF FC （This is the value that has been shifted right by 4 bits）, it corresponds to a large current value or a small current value？Thanks.

over 3 years ago

0 Mitch M over 3 years ago

TI__Mastermind 26345 points

Hello Hangjie,

That number would refer to a very small but negative current value.

Regards,

Mitch

0 Hangjie Wang over 3 years ago

TI__Intellectual 1230 points

Hello Mitch,

Could you please help explain how to convert this，thanks

0 Claus Edel over 3 years ago in reply to Hangjie Wang

Prodigy 120 points

#define SIGNED20(x) (int32_t)(((x) ^ 0x80000) - 0x80000)

uint32_t raw_current = read_INA229_register(0x07);
int32_t integer_current = SIGNED20(raw_current >> 4);

// rest as in 8.1.2 of the data sheet

0 Mitch M over 3 years ago in reply to Hangjie Wang

TI__Mastermind 26345 points

Hello Hangjie,

In addition to what Claus said, please have a look at our code generator/examples in SysConfig (https://dev.ti.com/sysconfig/index.html?product=ascstudio).

Here is a link to a project with the INA229 already added: https://dev.ti.com/sysconfig/index.html?product=ascstudio&module=/ti/sensors/currentsensor/INA229

For convenience, here is the section of code from the SysConfig project that reads the current register, shifts the data, adjusts for 2's compliment, and then converts the data based on the LSB:

Note that the conversion for 2's compliment is done in this manner because the 20 bit data is stored in an unsigned data type that is larger than 20 bits.

Regards,

Mitch

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INA229: INA229 Current Register