I2C CURRENT LEAK

RE: I2C CURRENT LEAK

KentOverton — Tue, 07 Jan 2025 13:37:41 GMT

Håkon,

I solved it in a diffefrent way

I added bias_pull_up and bias_pull_down statemts to the i2c pinctrl statements. They are now

i2c1_default: i2c1_default {

group1 {

psels = <NRF_PSEL(TWIM_SDA, 0, 34)>,

<NRF_PSEL(TWIM_SCL, 0, 37)>;

bias-pull-up;

};

i2c1_sleep: i2c1_sleep {

group1 {

psels = <NRF_PSEL(TWIM_SDA, 0, 34)>,

<NRF_PSEL(TWIM_SCL, 0, 37)>;

bias-pull-down;

};

When the i2c1 port is suspended SDA and SCL are quite low - less than a milli-VOLT.

When the i2c1 port is acrive SDA and SCL are at 3.3 Volts.

Håkon Alseth — Tue, 07 Jan 2025 13:22:17 GMT

Hi,

When using GPIO Port P1, you should describe it a bit different:

i2c1_default: i2c1_default {
group1 {
psels = <NRF_PSEL(TWIM_SDA, 1, 2)>,
<NRF_PSEL(TWIM_SCL, 1, 5)>;
//bias-pull-up;
};
};

[quote user=""]

In this state - (i2c initialized and suspended) I see around 100 mV on the SDA and SCL lines.

I expected to see no voltage there at all.

[/quote]

In this state the IOs will be floating, as there's no pull applied internally nor externally.

Kind regards,

Håkon

KentOverton — Mon, 06 Jan 2025 21:23:20 GMT

I had expected the suspend to fully idle the I2C signals - including removing the pull ups.

Turbo J — Mon, 06 Jan 2025 15:44:31 GMT

Idle state on the I²C lines is HIGH, i.e. being pulled up by the bus resistors. Why do you expect a low voltage here?