MM9Z1 Shunt Resistor Open Detection Issue

Shaojun — Tue, 03 Feb 2026 21:50:44 GMT

Dear support/community,

I'm working MM9Z1_638 microcontroller to measure current. So far everything looks fine. But once I enable open circuit detection for Shunt Resistor with

B_COMP_CTL = B_COMP_CTL_OPENEM_MASK | B_COMP_CTL_OPENE_MASK.

The sensor always outputs a constant current (0.6A for 50uOhm Shunt Resistor), even though the actual current is changing. And the OPEN bit in COMP_SR Register always indicates, the Shunt resistor is disconnected(OPEN = 1). Writing 1 also has no effect on this flag.

Please give me some suggestions or information about this issue.

Thanks!

Best regards,

Shaojun

SensorsのトピックMM9Z1 Shunt Resistor Open Detection Issue

MM9Z1 Shunt Resistor Open Detection Issue