Hello all,
I am facing a strange issue. I have custom boards with MSP430FR5738 on them. There are two switches connected on P1.1 and P1.2 in order to read discrete input states (either HIGH or LOW from switches) and a gate of MOSFET connected to P1.4. I assigned P1.4 as peripheral module function and PWM signal is driven from P1.4 with Timer_B0 module. Other pins are some 4-pin JTAG connections, VCC's are 3V and VSS's are ground. Rest of the pins are left open. I am not allowed to share schematic of the circuit since privacy policy of our company, but if you ask about more details, I will try to give more information.
The power consumption of the project is so strict, in order to make my battery life as long as possible, MSP430FR5738 needs to go in LPM4.5 while in sleep. It wakes up with interrupt from either of the switches.
In the datasheet, I found that MSP430FR573x series current is from 0.3 to 2.55 uA in LPM4.5 mode. That is what I exactly need.
So I programmed the microcontroller. In LPM4.5 entry, I configured unused pins of Port1 and Port2 as inputPinWithPullDownResistor, and unused pins of PortJ as inputPinWithPullUpResistor. There are no other ports in this microcontroller series. The two switch pins (P1.1 & P1.2) are left as input with interrupt enabled in order to make microcontroller wake up.
As I observed, some of my boards' current consumption is around 1.5 uA, which is good, but some of the boards' current consumption is around 250 - 300 uA.
I tried other options like setting unused pins as output and drive LOW when entering LPM4.5 but it just got worse. In that case, current consumption goes to 21mA.
We check over and over with hardware engineers and make ourselves sure that hardware is the same among all the boards and same software running on microcontrollers.
Can you please help us how to reduce current consumption of all boards to ~1uA level? Can you please share if there is an erradata workaround?
Best regards,
gorkem