diff --git a/myapps/practice/01-button/Makefile b/myapps/practice/01-button/Makefile
new file mode 100644
index 0000000..3560750
--- /dev/null
+++ b/myapps/practice/01-button/Makefile
@@ -0,0 +1,165 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/01-button/Makefile-fullsdk.bkp b/myapps/practice/01-button/Makefile-fullsdk.bkp
new file mode 100644
index 0000000..1bffc48
--- /dev/null
+++ b/myapps/practice/01-button/Makefile-fullsdk.bkp
@@ -0,0 +1,185 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_timer1.c \
+../../../vendor/StdPeriphDriver/CH59x_adc.c \
+../../../vendor/StdPeriphDriver/CH59x_flash.c \
+../../../vendor/StdPeriphDriver/CH59x_usb2hostBase.c \
+../../../vendor/StdPeriphDriver/CH59x_uart2.c \
+../../../vendor/StdPeriphDriver/CH59x_spi1.c \
+../../../vendor/StdPeriphDriver/CH59x_usbhostBase.c \
+../../../vendor/StdPeriphDriver/CH59x_timer3.c \
+../../../vendor/StdPeriphDriver/CH59x_usbhostClass.c \
+../../../vendor/StdPeriphDriver/CH59x_timer2.c \
+../../../vendor/StdPeriphDriver/CH59x_uart1.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_usb2hostClass.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_timer0.c \
+../../../vendor/StdPeriphDriver/CH59x_pwm.c \
+../../../vendor/StdPeriphDriver/CH59x_uart0.c \
+../../../vendor/StdPeriphDriver/CH59x_spi0.c \
+../../../vendor/StdPeriphDriver/CH59x_i2c.c \
+../../../vendor/StdPeriphDriver/CH59x_usbdev.c \
+../../../vendor/StdPeriphDriver/CH59x_usb2dev.c \
+../../../vendor/StdPeriphDriver/CH59x_uart3.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/01-button/src/main.c b/myapps/practice/01-button/src/main.c
new file mode 100644
index 0000000..90e3acf
--- /dev/null
+++ b/myapps/practice/01-button/src/main.c
@@ -0,0 +1,24 @@
+
+// LED: PA8 (active low)
+// BUT: PB22 (active low, no pullup)
+
+#include "CH59x_common.h"
+
+int main()
+{
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_8);  // LED
+  GPIOA_ModeCfg(GPIO_Pin_8, GPIO_ModeOut_PP_5mA);
+  
+  GPIOB_ModeCfg(GPIO_Pin_22, GPIO_ModeIN_PU);  // Button
+  
+  while(1) {
+    if (GPIOB_ReadPortPin(GPIO_Pin_22))
+      GPIOA_SetBits(GPIO_Pin_8);
+    else
+      GPIOA_ResetBits(GPIO_Pin_8);
+  }
+  
+}
+
diff --git a/myapps/practice/02-button-int/Makefile b/myapps/practice/02-button-int/Makefile
new file mode 100644
index 0000000..3560750
--- /dev/null
+++ b/myapps/practice/02-button-int/Makefile
@@ -0,0 +1,165 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/02-button-int/src/main.c b/myapps/practice/02-button-int/src/main.c
new file mode 100644
index 0000000..35dba0c
--- /dev/null
+++ b/myapps/practice/02-button-int/src/main.c
@@ -0,0 +1,33 @@
+// TODO fix line 27
+// LED: PA8 (active low)
+// BUT: PB22 (active low, no pullup)
+
+#include "CH59x_common.h"
+
+__INTERRUPT
+__HIGH_CODE
+void GPIOB_IRQHandler()
+{
+  if (GPIOB_ReadITFlagBit(GPIO_Pin_8)) {
+    GPIOA_InverseBits(GPIO_Pin_8);
+    GPIOB_ClearITFlagBit(GPIO_Pin_8);
+  }
+}
+
+int main()
+{
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_8);  // LED
+  GPIOA_ModeCfg(GPIO_Pin_8, GPIO_ModeOut_PP_5mA);
+  
+  GPIOB_ModeCfg(GPIO_Pin_22, GPIO_ModeIN_PU); // button
+  GPIOB_ITModeCfg(GPIO_Pin_8, GPIO_ITMode_FallEdge);  // PB8 mux'd as PB22 see below
+  GPIOB_ClearITFlagBit(GPIO_Pin_8);
+  GPIOPinRemap(ENABLE, RB_PIN_INTX); // <================== workaround, as R16_PB_INT reg is 16b wide
+  PFIC_EnableIRQ(GPIO_B_IRQn);
+  
+  while (1);
+  
+}
+
diff --git a/myapps/practice/02-button-int/src/main.c.bkp1 b/myapps/practice/02-button-int/src/main.c.bkp1
new file mode 100644
index 0000000..de2e6cc
--- /dev/null
+++ b/myapps/practice/02-button-int/src/main.c.bkp1
@@ -0,0 +1,41 @@
+
+// LED: PA8 (active low)
+// BUT: PB22 (active low, no pullup)
+
+#include "CH59x_common.h"
+#include <stdbool.h>
+
+volatile bool buttonPressed = false;
+
+__INTERRUPT
+__HIGH_CODE
+void GPIOB_IRQHandler()
+{
+  if (GPIOB_ReadITFlagBit(GPIO_Pin_8)) {
+    buttonPressed = true;
+    GPIOB_ClearITFlagBit(GPIO_Pin_8);
+  }
+}
+
+int main()
+{
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_8);  // LED
+  GPIOA_ModeCfg(GPIO_Pin_8, GPIO_ModeOut_PP_5mA);
+  
+  GPIOB_ModeCfg(GPIO_Pin_22, GPIO_ModeIN_PU); // button
+  GPIOB_ITModeCfg(GPIO_Pin_8, GPIO_ITMode_FallEdge);
+  GPIOB_ClearITFlagBit(GPIO_Pin_8);
+  GPIOPinRemap(ENABLE, RB_PIN_INTX); // <==================
+  PFIC_EnableIRQ(GPIO_B_IRQn);
+  
+  while (1) {
+    if (buttonPressed) {
+      buttonPressed = false;
+      GPIOA_InverseBits(GPIO_Pin_8);
+    }
+  }
+  
+}
+
diff --git a/myapps/practice/03-tmr-int/Makefile b/myapps/practice/03-tmr-int/Makefile
new file mode 100644
index 0000000..43923fb
--- /dev/null
+++ b/myapps/practice/03-tmr-int/Makefile
@@ -0,0 +1,166 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/StdPeriphDriver/CH59x_timer1.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/03-tmr-int/src/main.c b/myapps/practice/03-tmr-int/src/main.c
new file mode 100644
index 0000000..d2f2ff2
--- /dev/null
+++ b/myapps/practice/03-tmr-int/src/main.c
@@ -0,0 +1,32 @@
+
+// LED: PA8 (active low)
+
+#include "CH59x_common.h"
+#include <stdbool.h>
+
+__INTERRUPT
+__HIGH_CODE
+void TMR1_IRQHandler()
+{
+  //
+  if (TMR1_GetITFlag(TMR0_3_IT_CYC_END)) {
+    GPIOA_InverseBits(GPIO_Pin_8);
+    TMR1_ClearITFlag(TMR0_3_IT_CYC_END);
+  }
+}
+
+int main()
+{
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_8);  // LED
+  GPIOA_ModeCfg(GPIO_Pin_8, GPIO_ModeOut_PP_5mA);
+  
+  TMR1_TimerInit(30000000); // for 500ms
+  TMR1_ClearITFlag(TMR0_3_IT_CYC_END);
+  TMR1_ITCfg(true, TMR0_3_IT_CYC_END); //RB_TMR_IE_CYC_END, first bit
+  PFIC_EnableIRQ(TMR1_IRQn);
+  TMR1_Enable();
+  
+  while (1);
+}
diff --git a/myapps/practice/04-pwm/Makefile b/myapps/practice/04-pwm/Makefile
new file mode 100644
index 0000000..43923fb
--- /dev/null
+++ b/myapps/practice/04-pwm/Makefile
@@ -0,0 +1,166 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/StdPeriphDriver/CH59x_timer1.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/04-pwm/src/main.c b/myapps/practice/04-pwm/src/main.c
new file mode 100644
index 0000000..96f8770
--- /dev/null
+++ b/myapps/practice/04-pwm/src/main.c
@@ -0,0 +1,61 @@
+
+// TMR1/PWM1/CAP1: PA10 (active low)
+
+#include "CH59x_common.h"
+#include <stdbool.h>
+
+#define PWM_FREQ  1000
+#define PWM_PRD   FREQ_SYS/PWM_FREQ
+// 0 -> 60,000
+#define PWM_STEP  600
+// 600: 100 steps
+#define DELAY_STEP 50
+// 5 second fade in
+
+int main()
+{
+  int32_t d = 0;
+  bool rising = true;
+  
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_10); // PWM OUT
+  GPIOA_ModeCfg(GPIO_Pin_10, GPIO_ModeOut_PP_5mA);
+  
+  TMR1_PWMInit(Low_Level, PWM_Times_1); // Note: PWMX_PolarTypeDef defined in CH58x_pwm.h
+                      // Need to init before setting PWMCycleCfg & PWMActDataWidth
+  TMR1_PWMCycleCfg(PWM_PRD);
+  //TMR1_PWMActDataWidth(PWM_PRD*PWM_DUTY); // MAX value: TMR1_PWMCycleCfg above (for 100%)
+  TMR1_PWMActDataWidth(d); // MAX value: TMR1_PWMCycleCfg above (for 100%)
+  TMR1_PWMEnable(); // enables output pin, configured above
+  TMR1_Enable();
+  
+  while (1) {
+    
+    if (rising == true) {
+      
+      DelayMs(DELAY_STEP);
+      d += PWM_STEP;
+      
+      if (d == PWM_PRD)
+        rising = false;
+      
+      TMR1_Disable();
+      TMR1_PWMActDataWidth(d);
+      TMR1_Enable();
+    
+    } else {
+      
+      DelayMs(DELAY_STEP);
+      d -= PWM_STEP;
+      
+      if (d == 0)
+        rising = true;
+      
+      TMR1_Disable();
+      TMR1_PWMActDataWidth(d);
+      TMR1_Enable();
+    }
+  }
+  
+}
diff --git a/myapps/practice/04-pwm/src/main.c.fixedpulse b/myapps/practice/04-pwm/src/main.c.fixedpulse
new file mode 100644
index 0000000..c31ce71
--- /dev/null
+++ b/myapps/practice/04-pwm/src/main.c.fixedpulse
@@ -0,0 +1,26 @@
+
+// TMR1/PWM1/CAP1: PA10 (active low)
+
+#include "CH59x_common.h"
+
+#define PWM_FREQ  1000
+#define PWM_PRD   FREQ_SYS/PWM_FREQ
+#define PWM_DUTY  0.20
+
+int main()
+{
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  GPIOA_SetBits(GPIO_Pin_10); // PWM OUT
+  GPIOA_ModeCfg(GPIO_Pin_10, GPIO_ModeOut_PP_5mA);
+  
+  TMR1_PWMInit(Low_Level, PWM_Times_1); // Note: PWMX_PolarTypeDef defined in CH58x_pwm.h
+                      // Need to init before setting PWMCycleCfg & PWMActDataWidth
+  TMR1_PWMCycleCfg(PWM_PRD);
+  TMR1_PWMActDataWidth(PWM_PRD*PWM_DUTY); // MAX value: TMR1_PWMCycleCfg above (for 100%)
+  TMR1_PWMEnable(); // enables output pin, configured above
+  TMR1_Enable();
+  
+  while (1);
+  
+}
diff --git a/myapps/practice/05-pwm-dma/Makefile b/myapps/practice/05-pwm-dma/Makefile
new file mode 100644
index 0000000..43923fb
--- /dev/null
+++ b/myapps/practice/05-pwm-dma/Makefile
@@ -0,0 +1,166 @@
+######################################
+# target
+######################################
+TARGET = ch592_blinky
+# ../../
+
+
+######################################
+# building variables
+######################################
+# debug build?
+DEBUG = 1
+# optimization for size
+OPT = -Os
+
+
+#######################################
+# paths
+#######################################
+# Build path
+BUILD_DIR = build
+
+######################################
+# source
+######################################
+# C sources
+C_SOURCES = \
+src/main.c \
+../../../vendor/StdPeriphDriver/CH59x_clk.c \
+../../../vendor/StdPeriphDriver/CH59x_gpio.c \
+../../../vendor/StdPeriphDriver/CH59x_pwr.c \
+../../../vendor/StdPeriphDriver/CH59x_sys.c \
+../../../vendor/StdPeriphDriver/CH59x_timer1.c \
+../../../vendor/RVMSIS/core_riscv.c \
+
+
+# ASM sources
+ASM_SOURCES =  \
+../../../vendor/Startup/startup_CH592.S
+
+#######################################
+# binaries
+#######################################
+#PREFIX = riscv-none-elf-
+#PREFIX = riscv64-elf-
+#debian
+#PREFIX = riscv64-unknown-elf-
+PREFIX = riscv-wch-elf-
+
+CC = $(PREFIX)gcc
+AS = $(PREFIX)gcc -x assembler-with-cpp
+CP = $(PREFIX)objcopy
+SZ = $(PREFIX)size
+
+HEX = $(CP) -O ihex
+BIN = $(CP) -O binary -S
+
+#######################################
+# CFLAGS
+#######################################
+# cpu
+CPU = -march=rv32imac_zicsr -mabi=ilp32 -msmall-data-limit=8 
+
+# For gcc version less than v12
+# CPU = -march=rv32imac -mabi=ilp32 -msmall-data-limit=8
+
+# fpu
+FPU = 
+
+# float-abi
+FLOAT-ABI =
+
+# mcu
+MCU = $(CPU) $(FPU) $(FLOAT-ABI)
+
+# AS includes
+AS_INCLUDES = 
+
+# C includes
+C_INCLUDES =  \
+-I../../../vendor/StdPeriphDriver/inc \
+-I../../../vendor/RVMSIS \
+-I../../../vendor/Core \
+-Isrc/include
+
+# compile gcc flags
+ASFLAGS = $(MCU) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+CFLAGS = $(MCU) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
+
+ifeq ($(DEBUG), 1)
+CFLAGS += -g -gdwarf-2
+endif
+
+
+# Generate dependency information
+CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)"
+
+
+#######################################
+# LDFLAGS
+#######################################
+# link script
+LDSCRIPT = ../../../vendor/Ld/Link.ld 
+
+# libraries
+LIBS = -lc -lm -lnosys ../../../vendor/StdPeriphDriver/libISP592.a
+LIBDIR = 
+LDFLAGS = $(MCU) -mno-save-restore -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wunused -Wuninitialized -T $(LDSCRIPT) -nostartfiles -Xlinker --gc-sections -Wl,-Map=$(BUILD_DIR)/$(TARGET).map --specs=nano.specs $(LIBS)
+
+# default action: build all
+all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).hex $(BUILD_DIR)/$(TARGET).bin
+
+
+#######################################
+# build the application
+#######################################
+# list of objects
+OBJECTS = $(addprefix $(BUILD_DIR)/,$(notdir $(C_SOURCES:.c=.o)))
+vpath %.c $(sort $(dir $(C_SOURCES)))
+
+# list of ASM program objects
+OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.S=.o)))
+vpath %.S $(sort $(dir $(ASM_SOURCES)))
+
+$(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
+	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+
+$(BUILD_DIR)/%.o: %.S Makefile | $(BUILD_DIR)
+	$(AS) -c $(CFLAGS) $< -o $@
+#$(LUAOBJECTS) $(OBJECTS)
+$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	$(SZ) $@
+
+$(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(HEX) $< $@
+	
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
+	$(BIN) $< $@	
+	
+$(BUILD_DIR):
+	mkdir $@		
+
+#######################################
+# Program
+#######################################
+
+isp: $(BUILD_DIR)/$(TARGET).bin
+	wchisp flash $(BUILD_DIR)/$(TARGET).bin
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	wlink flash $(BUILD_DIR)/$(TARGET).bin
+
+#######################################
+# clean up
+#######################################
+clean:
+	-rm -fR $(BUILD_DIR)
+  
+#######################################
+# dependencies
+#######################################
+-include $(wildcard $(BUILD_DIR)/*.d)
+
+# *** EOF ***
diff --git a/myapps/practice/05-pwm-dma/src/main.c b/myapps/practice/05-pwm-dma/src/main.c
new file mode 100644
index 0000000..6992113
--- /dev/null
+++ b/myapps/practice/05-pwm-dma/src/main.c
@@ -0,0 +1,49 @@
+
+// TMR1/PWM1/CAP1: PA10 (active low)
+
+#include "CH59x_common.h"
+#include <stdbool.h>
+
+#define PWM_FREQ  1000
+#define PWM_PRD   FREQ_SYS/PWM_FREQ
+// 0 -> 60,000
+#define PWM_STEP  240
+// 125 steps
+#define TABLE_SIZE 500
+
+uint32_t step_table[TABLE_SIZE];    // need to use 32bit register to match 'FIFO' reg
+
+void load_dma()
+{
+  uint16_t i = 0;
+  for (uint32_t n = 0; n < PWM_PRD; n += PWM_STEP) {
+    step_table[i] = n;
+    i++;
+  }
+  for (uint32_t n = PWM_PRD; n > 0; n -= PWM_STEP) {
+    step_table[i] = n;
+    i++;
+  }
+}
+
+int main()
+{
+  
+  SetSysClock(CLK_SOURCE_PLL_60MHz);
+  
+  load_dma();
+  
+  GPIOA_SetBits(GPIO_Pin_10); // PWM OUT
+  GPIOA_ModeCfg(GPIO_Pin_10, GPIO_ModeOut_PP_5mA);
+  
+  TMR1_PWMInit(Low_Level, PWM_Times_8); // Note: PWMX_PolarTypeDef defined in CH58x_pwm.h
+                      // Need to init before setting PWMCycleCfg & PWMActDataWidth
+  TMR1_DMACfg(ENABLE, (uint16_t)(uint32_t)step_table, (uint16_t)(uint32_t)&step_table[TABLE_SIZE], true);
+  TMR1_PWMCycleCfg(PWM_PRD);
+  TMR1_PWMActDataWidth(0); // MAX value: TMR1_PWMCycleCfg above (for 100%)
+  TMR1_PWMEnable(); // enables output pin, configured above
+  TMR1_Enable();
+  
+  while (1);
+  
+}