From 6ef35fc634f577682da5157fea4653a4c7d65de6 Mon Sep 17 00:00:00 2001
From: Ruben Dashyan <ruben.dashyan@numworks.com>
Date: Mon, 14 Jan 2019 16:45:40 +0100
Subject: [PATCH] [ion/f730] Under-drive stop mode

---
 ion/src/f730/power.cpp  |  6 ++++--
 ion/src/f730/regs/pwr.h | 11 +++++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/ion/src/f730/power.cpp b/ion/src/f730/power.cpp
index 021d75cc6..d18854bf5 100644
--- a/ion/src/f730/power.cpp
+++ b/ion/src/f730/power.cpp
@@ -20,8 +20,10 @@ void Ion::Power::suspend(bool checkIfPowerKeyReleased) {
   }
   Device::shutdownPeripherals(isLEDActive);
 
-  PWR.CR()->setLPDS(true); // Turn the regulator off. Takes longer to wake up.
-  PWR.CR()->setFPDS(true); // Put the flash to sleep. Takes longer to wake up.
+  PWR.CR1()->setLPDS(true); // Turn the regulator off. Takes longer to wake up.
+  PWR.CR1()->setFPDS(true); // Put the flash to sleep. Takes longer to wake up.
+  PWR.CR1()->setLPUDS(true);
+  PWR.CR1()->setUDEN(PWR::CR1::UnderDrive::Enable);
   CM4.SCR()->setSLEEPDEEP(!isLEDActive);
 
   while (1) {
diff --git a/ion/src/f730/regs/pwr.h b/ion/src/f730/regs/pwr.h
index 089d72e18..f3cef32d7 100644
--- a/ion/src/f730/regs/pwr.h
+++ b/ion/src/f730/regs/pwr.h
@@ -5,15 +5,22 @@
 
 class PWR {
 public:
-  class CR : Register32 {
+  class CR1 : Register32 {
   public:
+    enum class UnderDrive {
+      Disable = 0,
+      Enable = 3
+    };
     REGS_BOOL_FIELD(LPDS, 0);
     REGS_BOOL_FIELD(PPDS, 1);
     REGS_BOOL_FIELD(FPDS, 9);
+    REGS_BOOL_FIELD(LPUDS, 10);
+    REGS_BOOL_FIELD(MRUDS, 11);
+    REGS_FIELD_W(UDEN, UnderDrive, 19, 18);
   };
 
   constexpr PWR() {};
-  REGS_REGISTER_AT(CR, 0x00);
+  REGS_REGISTER_AT(CR1, 0x00);
 private:
   constexpr uint32_t Base() const {
     return 0x40007000;