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Diffstat (limited to 'Documentation/getting_started/gpio.md')
| -rw-r--r-- | Documentation/getting_started/gpio.md | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/getting_started/gpio.md b/Documentation/getting_started/gpio.md index 13aeed5bd2..d4e8ca7df4 100644 --- a/Documentation/getting_started/gpio.md +++ b/Documentation/getting_started/gpio.md @@ -129,3 +129,13 @@ If no pullup or pulldown is declared with these, they may end up "floating", i.e., not at logical high or logical low. This can cause problems such as unwanted power consumption or not reading the pin correctly, if it was intended to be strapped. + +## Pad-related known issues and workarounds + +### LPC_CLKRUNB blocks S0ix states when board uses eSPI + +When using eSPI, the pad implementing `LPC_CLKRUNB` must be set to GPIO mode. +Other pin settings i.e. Rx path enable/disable, Tx path enable/disable, pull up +enable/disable etc are ignored. Leaving this pin in native mode will keep the +LPC Controller awake and prevent S0ix entry. This issues is know at least on +Apollolake and Geminilake. |