alif/boards/OPENMV_AE3: Save power upon deepsleep.

dpgeorge · dpgeorge · commit 414fcbf38bc4 · 2026-03-04T01:02:29.000+11:00
It's now down to 80uA in `machine.deepsleep()`.

Signed-off-by: Damien George &lt;damien@micropython.org&gt;
diff --git a/ports/alif/boards/OPENMV_AE3/board.c b/ports/alif/boards/OPENMV_AE3/board.c
@@ -139,17 +139,21 @@ void board_early_init(void) {
         // CLK_SRC_HFRC, CLK_SRC_HFXO or CLK_SRC_PLL
         .stby_clk_src = CLK_SRC_HFRC,
         .stby_clk_freq = SCALED_FREQ_RC_STDBY_76_8_MHZ,
-        // Disable all power domains.
-        .power_domains = 0,
-        // Add all memories
-        .memory_blocks = SERAM_MASK | SRAM0_MASK | SRAM1_MASK | MRAM_MASK | BACKUP4K_MASK |
-            SRAM6A_MASK | SRAM6B_MASK | SRAM7_1_MASK | SRAM7_2_MASK | SRAM7_3_MASK |
-            SRAM8_MASK | SRAM9_MASK | FWRAM_MASK,
+        // Disable all power domains except AON.
+        .power_domains = PD_VBAT_AON_MASK,
+        // Keep SERAM, MRAM and backup SRAM on.
+        // (SRAM0 also needs to stay on because it's used for .bss.sram0 which is zerod
+        // by the runtime before the run profile is configured.)
+        .memory_blocks = SERAM_MASK | SRAM0_MASK | MRAM_MASK | BACKUP4K_MASK,
+        // Gate the clocks of IP blocks.
+        .ip_clock_gating = 0x3ffb,
+        // Gate PHY power (saves 0.5uA).
         .phy_pwr_gating = LDO_PHY_MASK | USB_PHY_MASK | MIPI_TX_DPHY_MASK | MIPI_RX_DPHY_MASK |
             MIPI_PLL_DPHY_MASK,
         .vdd_ioflex_3V3 = IOFLEX_LEVEL_3V3,
         .vtor_address = SCB->VTOR,
         .vtor_address_ns = SCB->VTOR,
+        // Configure wake-up sources.
         .ewic_cfg = EWIC_RTC_A,
         .wakeup_events = WE_LPRTC,
     };
@@ -165,6 +169,14 @@ void board_early_init(void) {
 }
 
 MP_WEAK void board_enter_stop(void) {
+    // Let USB_D_SEL float, so it doesn't source 30uA through the 110k resistors to GND.
+    mp_hal_pin_input(pin_USB_D_SEL);
+
+    #if MICROPY_HW_ENABLE_OSPI
+    // SPI deep power down reduces deepsleep consumption by about 10uA at 3.3V.
+    ospi_flash_sleep();
+    #endif
+
     // Disable NPU interrupt
     NVIC_DisableIRQ(NPU_IRQ_NUMBER);
     NVIC_ClearPendingIRQ(NPU_IRQ_NUMBER);
