added window watchdog module and tests.

src/CMakeLists.txt

@@ -12,6 +12,7 @@ target_include_directories(${PROJECT_NAME} PUBLIC
 
 target_link_libraries(${PROJECT_NAME} PRIVATE 
     #blink
+    wwdg
     gcc
 )
 
@@ -62,3 +63,4 @@ add_custom_command(TARGET ${PROJECT_NAME} POST_BUILD
 add_subdirectory(ADC)
 add_subdirectory(RegEdit)
 add_subdirectory(blink)
+add_subdirectory(wwdg)

src/wwdg/CMakeLists.txt

@@ -0,0 +1,49 @@
+# File: src/wwdg/CMakeLists.txt
+add_library(wwdg STATIC
+    wwdg.c
+)
+
+# Current list dir: The directory where the cmake config file is.
+# Source Dir: The dir where the root/main cmake config file is.
+
+if(NOT UNIT_TESTING)
+    target_include_directories(wwdg PUBLIC
+        ${CMAKE_CURRENT_LIST_DIR}
+        ${CMAKE_SOURCE_DIR}/inc/
+    )
+    target_link_libraries(wwdg
+        RegEdit
+    )
+
+    target_compile_options(wwdg PUBLIC
+    -g
+    -Os
+    -flto
+    -ffunction-sections
+    -fdata-sections
+    -fmessage-length=0
+    -msmall-data-limit=8
+    -march=rv32ec
+    -mabi=ilp32e
+    )
+
+
+else()
+    target_include_directories(wwdg PUBLIC
+        ${CMAKE_CURRENT_LIST_DIR}
+        #First we include any module specific test dependencies.
+        ${CMAKE_SOURCE_DIR}/tests/wwdg/mocks/
+        ${CMAKE_SOURCE_DIR}/tests/wwdg/fakes/
+        ${CMAKE_SOURCE_DIR}/tests/wwdg/stubs/
+        #Next comes the shared and non-module specific test depencencies.
+        ${CMAKE_SOURCE_DIR}/tests/shared/mocks/
+        ${CMAKE_SOURCE_DIR}/tests/shared/fakes/
+        ${CMAKE_SOURCE_DIR}/tests/shared/stubs/
+        #Finally we include the local stuff, which has likely been overridden.
+        ${CMAKE_CURRENT_SOURCE_DIR}
+    )
+    #Place Mocked/Regular dependencies here for unit testing.
+    target_link_libraries(wwdg
+        MockRegEdit
+    )
+endif()

src/wwdg/wwdg.c

@@ -0,0 +1,91 @@
+/*
+ * Author: Jake G
+ * Date: 2026
+ * filename: wwdg.c
+ * description: Source for window watchdog implimentation.
+ */
+
+#include "wwdg.h"
+#include "RegEdit.h"
+#include "ch32fun.h"
+
+#define WWDG_MIN_WINDOW_VAL 0x40 // 64
+#define WWDG_MAX_WINDOW_VAL 0x7F // 127
+
+static inline void wwdg_rcc_enable(void)
+{
+    // RegEdit_u32_AND_Num((void *)&RCC->APB1PCENR, RCC_WWDGEN);
+    RegEdit_u32_SetBit((void *)&RCC->APB1PCENR, RCC_WWDGEN_BIT);
+}
+
+void wwdg_enable(void)
+{
+    wwdg_rcc_enable();
+    RegEdit_u32_SetBit((void *)&WWDG->CTLR, WWDG_CTLR_WDGA_BIT);
+    return;
+}
+
+// maybe this should actually set the reset bit in the APB1 reg?
+void wwdg_disable(void)
+{
+    RegEdit_u32_ClearBit((void *)&RCC->APB1PCENR, RCC_WWDGEN_BIT);
+    return;
+}
+
+bool wwdg_set_clock_div(uint8_t div)
+{
+    if (div > 3)
+    {
+        return false;
+    }
+
+    RegEdit_u16_ClearBit((void *)&WWDG->CFGR, 7);
+    RegEdit_u16_ClearBit((void *)&WWDG->CFGR, 8);
+    RegEdit_u16_OR_Num((void *)&WWDG->CFGR, div);
+
+    return true;
+}
+
+bool wwdg_set_window(uint8_t value)
+{
+    // Check if either the input is bigger than 7-Bits or less than the min.
+    if (value < WWDG_MIN_WINDOW_VAL || value > WWDG_MAX_WINDOW_VAL)
+    {
+        return false;
+    }
+
+    // First we clear the value in the first 7-Bits.
+    //  UINT16_MAX & ~127 = 0xFF80, aka bits [0:6]
+    RegEdit_u16_AND_Num((void *)&WWDG->CFGR, 0xFF80);
+
+    // Now we set the value.
+    RegEdit_u16_OR_Num((void *)&WWDG->CFGR, value);
+
+    return true;
+}
+
+bool wwdg_reset_timer(uint8_t reset_value)
+{
+    if (reset_value > WWDG_MAX_WINDOW_VAL || reset_value < WWDG_MIN_WINDOW_VAL)
+    {
+        return false;
+    }
+
+    // Clear the last six bits
+    RegEdit_u16_AND_Num((void *)&WWDG->CTLR, 0xFF80);
+
+    // Set the last six bits.
+    RegEdit_u16_OR_Num((void *)&WWDG->CTLR, reset_value);
+
+    return true;
+}
+
+void wwdg_enable_interrupt(void)
+{
+    RegEdit_u16_SetBit((void *)&WWDG->CFGR, WWDG_EWI_BIT);
+}
+
+void wwdg_disable_interrupt(void)
+{
+    RegEdit_u16_ClearBit((void *)&WWDG->CFGR, WWDG_EWI_BIT);
+}

src/wwdg/wwdg.h

@@ -0,0 +1,133 @@
+/**
+ * @brief Window Watchdog Timer Module.
+ * @details Window Watchdog Timer with bi-conditional reset.
+ * @author Jake G
+ * @date 2026
+ * @copyright None
+ * @file wwdg.h
+ *
+ * Used to monitor system operation for software faults such as external
+ * disturbances unforseen logic errors and other conditions. It requires a
+ * counter refresh(dog feeding) within a specific window time(with upper and
+ * lower limits), otherwise earlier or later than this window time the
+ * watchdog circuit will generate a system reset.
+ *
+ * This is clocked off the AHB like so:
+ *
+ * AHB --> /4096 --> WDGTB
+ *
+ * Where the WDGTB is a user changable divdider.
+ *
+ *
+ * The minimum value also known as T3 is 0x40. When 0x40 is in the register the
+ * watchdog will have timed out.
+ */
+
+// #pragma once
+#ifndef WWDG_H
+#define WWDG_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include <math.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define LOG2(x) (log(x) / log(2))
+
+// These use the ch32fun defines and log to extract the bit position numbers.
+// Those numbers are then used in the regedit module's functions.
+#define RCC_WWDGEN_BIT LOG2(RCC_WWDGEN)
+#define WWDG_CTLR_WDGA_BIT LOG2(WWDG_CTLR_WDGA)
+#define WWDG_EWI_BIT LOG2(WWDG_CFGR_EWI)
+
+#define WWDG_MAX_VALUE 127
+
+    enum WWDG_DIVS
+    {
+        DIV_ONE   = 0,
+        DIV_TWO   = 1,
+        DIV_FOUR  = 2,
+        DIV_EIGHT = 3,
+    };
+
+    typedef struct
+    {
+        uint8_t upper_limit;
+        uint8_t reset_value;
+        uint8_t clk_divider;
+        bool enable_ewi;
+    } WWDT_Config;
+
+    // struct WWDG;
+
+    /*
+     * @brief
+     * @param
+     */
+    void wwdg_setup(WWDT_Config *conf);
+
+    /*
+     * @brief Enables the Window Watchdog Timer.
+     * After the WWDG is enabled it cannot be disabled until the entire
+     * system is reset.
+     *
+     * The watchdog can technically be stopped from operating by disabling the
+     * AHB clock bit for it using the RCC register.
+     */
+    void wwdg_enable(void);
+
+    /**
+     * @brief Disables the Window Watchdog Timer.
+     * This function doesn't actully disable the peripheral itself but
+     * disables the clock bit that supplies the WWDG.
+     */
+    void wwdg_disable(void);
+
+    /**
+     * @brief Set's the clock divider value.
+     * @param[in] Divider value from 0-3 are valid as it's a 2Bit value.
+     * @return False on invalid dividers, true on success.
+     *
+     * 0: Divide by 1, aka do nothing.
+     * 1: Divide by 2.
+     * 2: Divide by 4.
+     * 3: Divide by 8.
+     */
+    bool wwdg_set_clock_div(uint8_t div);
+
+    /**
+     * @brief Sets the WWDG upper threshold.
+     * @param[in] 7-Bit counter value.
+     *
+     * The function set's the W[6:0] or upper threshold value that that the
+     * counter must be less than or equal to in order to refresh the WWDG,
+     * aka feed the dog.
+     */
+    bool wwdg_set_window(uint8_t value);
+
+    /**
+     * @brief Resets the WWDT counter.
+     * @param[in] The value the counter will be set, must be 7-Bit value.
+     */
+    bool wwdg_reset_timer(uint8_t reset_value);
+
+    /**
+     * @brief Enables the early wakeup interrupt bit.
+     */
+    void wwdg_enable_interrupt(void);
+
+    /**
+     * @brief Disables the early wakeup interrupt bit.
+     */
+    void wwdg_disable_interrupt(void);
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus
+
+#endif // WWDG_H

tests/wwdg/CMakeLists.txt

@@ -0,0 +1,24 @@
+# File: tests/wwdg/CMakeLists.txt
+
+add_subdirectory(mocks)
+add_subdirectory(fakes)
+add_subdirectory(stubs)
+
+# TEST_RUNNER
+add_library(test_wwdg
+    test_wwdg.cpp    
+)
+
+target_link_libraries(test_wwdg
+    ${CPPUTEST_LIBRARIES}
+    wwdg
+)
+
+target_include_directories(test_wwdg PUBLIC
+    ${CMAKE_CURRENT_LIST_DIR}
+    #Next comes the shared and non-module specific test depencencies.
+    ${CMAKE_SOURCE_DIR}/inc/
+    ${CMAKE_SOURCE_DIR}/tests/shared/mocks/
+    ${CMAKE_SOURCE_DIR}/tests/shared/fakes/
+    ${CMAKE_SOURCE_DIR}/tests/shared/stubs/
+)

tests/wwdg/test_wwdg.cpp

@@ -0,0 +1,162 @@
+/*
+ * Author: username
+ * Date: todays_date 
+ * filename: test_wwdg.c
+ * description: module_purpose
+ */
+
+#include "CppUTest/CommandLineTestRunner.h"
+#include "CppUTestExt/MockSupport.h"
+
+extern "C" 
+{
+#include "ch32fun.h"
+#include "wwdg.h"
+}
+
+TEST_GROUP(tg_wwdg)
+{
+    void setup()
+    {
+
+    }
+    void teardown()
+    {
+        mock().checkExpectations();
+        mock().clear();
+    }
+};
+
+
+TEST(tg_wwdg, EnableCallsCorrectFunctiions)
+{
+    //The APB1 contains the WWDG peripheral.
+    mock().expectOneCall("RegEdit_u32_SetBit")
+        .withPointerParameter("reg", (void *)&RCC->APB1PCENR)
+        .withUnsignedIntParameter("bit_num", RCC_WWDGEN_BIT);
+
+    mock().expectOneCall("RegEdit_u32_SetBit")
+        .withPointerParameter("reg", (void *)&WWDG->CTLR)
+        .withUnsignedIntParameter("bit_num", WWDG_CTLR_WDGA_BIT);
+
+    wwdg_enable();
+}
+
+TEST(tg_wwdg, DisableWWDG_DisablesPeriphClock)
+{
+    mock().expectOneCall("RegEdit_u32_ClearBit")
+        .withPointerParameter("reg", (void *)&RCC->APB1PCENR)
+        .withUnsignedIntParameter("bit_num", RCC_WWDGEN_BIT);
+    wwdg_disable();
+}
+
+TEST(tg_wwdg, SetClockDivReturnsFalseOnInvalidValues)
+{
+    for(uint8_t i = 4; i > 10; i++){
+        CHECK_FALSE(wwdg_set_clock_div(i));
+    }
+}
+
+TEST(tg_wwdg, SetClockDivReturnsTrueOnValidValues)
+{
+    for(uint8_t i = 0; i <= 3; i++){
+        mock().expectOneCall("RegEdit_u16_ClearBit")
+            .withPointerParameter("reg", (void *)&WWDG->CFGR)
+            .withUnsignedIntParameter("bit_num", 7);
+        mock().expectOneCall("RegEdit_u16_ClearBit")
+            .withPointerParameter("reg", (void *)&WWDG->CFGR)
+            .withUnsignedIntParameter("bit_num", 8);
+
+        mock().expectOneCall("RegEdit_u16_OR_Num")
+            .withPointerParameter("reg", (void *)&WWDG->CFGR)
+            .withUnsignedIntParameter("num", i);
+    }
+
+    for(uint8_t i = 0; i <= 3; i++){
+        CHECK_TRUE(wwdg_set_clock_div(i));
+    }
+}
+
+
+TEST(tg_wwdg, SetWindowCounterReturnsFalseOnInvalidInputs)
+{
+    //We take all zeros logically and'd with the first six bits inverted.
+    //uint16_t mask = UINT16_MAX & ~127; //0xFF80
+    uint8_t value = 0;
+    bool ret = true;
+
+    for(value = 0; value < 0x3F; value++){
+        ret = wwdg_set_window(value);
+        CHECK_EQUAL(false, ret);
+    }
+    for(value = 128; value < 255; value++){
+        ret = wwdg_set_window(value);
+        CHECK_EQUAL(false, ret);
+    }
+}
+
+TEST(tg_wwdg, SetWindowCounterReturnsTrueOnValidInputs)
+{
+    //We take all zeros logically and'd with the first six bits inverted.
+    uint16_t mask = UINT16_MAX & ~127; //0xFF80
+    uint8_t value = 0;
+    bool ret = true;
+
+    for(value = 0x40; value <= 127; value++){
+        //The first bits 0:6 need to be cleared before being set.
+        mock().expectOneCall("RegEdit_u16_AND_Num")
+            .withPointerParameter("reg", (void *)&WWDG->CFGR)
+            .withUnsignedIntParameter("num", mask);
+
+        mock().expectOneCall("RegEdit_u16_OR_Num")
+            .withPointerParameter("reg", (void *)&WWDG->CFGR)
+            .withUnsignedIntParameter("num", value);
+    }
+
+    for(value = 0x40; value <= 127; value++){
+        ret = wwdg_set_window(value);
+        CHECK_EQUAL(true, ret);
+    }
+}
+
+TEST(tg_wwdg, SetEalryWakeUpSetsBit)
+{
+    mock().expectOneCall("RegEdit_u16_SetBit")
+        .withPointerParameter("reg", (void *)&WWDG->CFGR)
+        .withUnsignedIntParameter("bit_num", WWDG_EWI_BIT);
+
+    wwdg_enable_interrupt();
+}
+
+
+TEST(tg_wwdg, ClearEalyWakeUpClearsBit)
+{
+    mock().expectOneCall("RegEdit_u16_ClearBit")
+        .withPointerParameter("reg", (void *)&WWDG->CFGR)
+        .withUnsignedIntParameter("bit_num", WWDG_EWI_BIT);
+
+    wwdg_disable_interrupt();
+}
+
+TEST(tg_wwdg, ResetFunctionSetsRegister)
+{
+    //uint16_t fake_reg = 0;
+    uint16_t reset_value = 126;
+
+    /*
+    mock().expectOneCall("RegEdit_u16_ReadReg")
+        .withPointerParameter("reg", (void *)&WWDG->CTLR);
+        //.andReturnValue();
+    */
+
+    mock().expectOneCall("RegEdit_u16_AND_Num")
+        .withPointerParameter("reg", (void *)&WWDG->CTLR)
+        .withUnsignedIntParameter("num", 0xFF80);
+
+    mock().expectOneCall("RegEdit_u16_OR_Num")
+        .withPointerParameter("reg", (void *)&WWDG->CTLR)
+        .withUnsignedIntParameter("num", reset_value);
+
+    CHECK_TRUE(wwdg_reset_timer(reset_value));
+}
+