diff options
| author | Ravi Chandra Sadineni <ravisadineni@chromium.org> | 2019-10-27 16:05:38 -0700 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2019-10-31 00:08:09 +0000 |
| commit | b64ff5df1f93d5233cc257d08e451d71c5522d11 (patch) | |
| tree | 3b687c8fa9c0acf544b8d3bf07379cef941a0786 /board | |
| parent | e0f25be8962020e9836790ee2078720f16191238 (diff) | |
| download | chrome-ec-b64ff5df1f93d5233cc257d08e451d71c5522d11.tar.gz | |
hatch_fp: Configure unused GPIO pins.
By default, STM32F4 pins are configured as inputs, except some JTAG pins
which can impact the power consumption of the device in different power
modes because pins are very sensitive to external noise in input mode I/O.
To avoid extra I/O current, all pins should be configured as analog input
(AIN); in this mode the Schmitt trigger input is disabled, providing zero
consumption for each I/O pin.
For more info please look at "USING STM32F4 MCU POWER MODES WITH BEST
DYNAMIC EFFICIENCY"("AN4365") section 1.2.6 and STM32F412 reference manual
section 7.3.12.
BUG=b:130561737
BRANCH=None
TEST=Flash bloonchipper and measure power before and after. fpenroll and
fpmatch works fine.
Change-Id: I85d76589be22b892c81680763cfb263746004a80
Signed-off-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1883127
Reviewed-by: Craig Hesling <hesling@chromium.org>
Reviewed-by: Tom Hughes <tomhughes@chromium.org>
Diffstat (limited to 'board')
| -rw-r--r-- | board/hatch_fp/gpio.inc | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/board/hatch_fp/gpio.inc b/board/hatch_fp/gpio.inc index 7a9dfd152f..757cdfaf52 100644 --- a/board/hatch_fp/gpio.inc +++ b/board/hatch_fp/gpio.inc @@ -21,6 +21,21 @@ GPIO(FP_RST_ODL, PIN(B,10), GPIO_OUT_HIGH) GPIO(SPI2_NSS, PIN(B,12), GPIO_OUT_HIGH) GPIO(USER_PRES_L, PIN(B, 9), GPIO_ODR_HIGH) +/* + * Unused pins. + * Configuring unused pins as ANALOG INPUT to save power. For more info + * look at "USING STM32F4 MCU POWER MODES WITH BEST DYNAMIC EFFICIENCY" + * ("AN4365") section 1.2.6 and STM32F412 reference manual section 7.3.12. + */ +GPIO(UNUSED_PA2, PIN(A, 2), GPIO_ANALOG) +GPIO(UNUSED_PA3, PIN(A, 3), GPIO_ANALOG) +GPIO(UNUSED_PA8, PIN(A, 8), GPIO_ANALOG) +GPIO(UNUSED_PC13, PIN(C, 13), GPIO_ANALOG) +GPIO(UNUSED_PC14, PIN(C, 14), GPIO_ANALOG) +GPIO(UNUSED_PC15, PIN(C, 15), GPIO_ANALOG) +GPIO(UNUSED_PH0, PIN(H, 0), GPIO_ANALOG) +GPIO(UNUSED_PH1, PIN(H, 1), GPIO_ANALOG) + UNIMPLEMENTED(ENTERING_RW) /* USART1: PA9/PA10 */ |