LPC

LPC Demo Code Support List

This chapter introduces the details of the LPC demo code.

LPC Demo for Comparator Function

The description of LPC demo code 1 is shown in the following table.

LPC Demo Code 1 Description

Demo 1	lpc_comparator_demo.c
Sample Purpose	Demonstrate LPC comparator function.
File Path	sdk\src\sample\io_demo\lpc\comparator\lpc_comparator_demo.c
Function Entry	lpc_comparator_demo()
Hardware Connection	Connect M0_0 of EVB to an external DC voltage source.
Expected Result	Adjust the DC voltage source repeatedly, when the input voltage on M0_0 is detected to be higher than 400mV for 4 times, the string lpc_rtc_handler: lpc_counter_value 4 will be printed on Debug Analyzer.

LPC Demo for Voltage Detection (Input Below Threshold)

The description of LPC demo code 2 is shown in the following table.

LPC Demo Code 2 Description

Demo 2	lpc_peri_vol_demo.c
Sample Purpose	Demonstrate LPC voltage detection function.
File Path	sdk\src\sample\io_demo\lpc\voltage_detection\lpc_peri_vol_demo.c
Function Entry	lpc_peri_vol_demo()
Hardware Connection	Connect M0_0 of EVB to an external DC voltage source.
Expected Result	Adjust the DC voltage source, when the input voltage on M0_0 is detected to be lower than 800mV for 6 times, the string lpc_handler: lpc_counter_value 6 will be printed on Debug Analyzer.

LPC Demo for Voltage Detection (Input Over Threshold)

The description of LPC demo code 3 is shown in the following table.

LPC Demo Code 3 Description

Demo 3	lpc_rtc_vol_demo.c
Sample Purpose	Demonstrate LPC voltage detection function.
File Path	sdk\src\sample\io_demo\lpc\voltage_detection\lpc_rtc_vol_demo.c
Function Entry	lpc_rtc_vol_demo()
Hardware Connection	Connect M0_0 of EVB to an external DC voltage source.
Expected Result	Adjust the DC voltage source, when the input voltage on M0_0 is detected to be higher than 1200mV for 5 times, the string lpc_rtc_handler: lpc_counter_value 5 will be printed on Debug Analyzer.

Functional Overview

LPC can be used for voltage detection and counting. When the LPC detects that the input voltage exceeds the set voltage threshold, the system will trigger the interrupt. LPC can be used to count the number of times the input voltage exceeds the set voltage threshold. When the count value exceeds the set value of the comparator, the interrupt will be triggered.

Program Examples

Comparator Function Operation Flow

LPC comparator function initialization flow is shown in the following figure.

LPC Comparator Function Initialization Flow Chart

The codes below demonstrate the LPC comparator function initialization flow.

void driver_lpc_init(void)
{
   LPC_InitTypeDef LPC_InitStruct;
   LPC_StructInit(&LPC_InitStruct);
   LPC_InitStruct.LPC_Channel   = LPC_CAPTURE_PIN;
   LPC_InitStruct.LPC_Edge      = LPC_Vin_Over_Vth;
   LPC_InitStruct.LPC_Threshold = LPC_400_mV;
   LPC_Init(&LPC_InitStruct);

   LPC_CounterReset();
   LPC_WriteComparator(LPC_COMP_VALUE);
   LPC_INTConfig(LPC_INT_COUNT_COMP, ENABLE);

#if (TARGET_RTL87X3E == 1 || CONFIG_SOC_SERIES_RTL8773E == 1)
   RTC_CpuNVICEnable(ENABLE);
   RamVectorTableUpdate(RTC_VECTORn, lpc_rtc_handler);
   /* Config LPC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = RTC_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);
#else
   LPC_INTConfig(LPC_INT_VOLTAGE_COMP, ENABLE);
   RamVectorTableUpdate(LPCOMP_VECTORn, lpc_rtc_handler);
   /* Config LPC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = LPCOMP_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);
#endif

   LPC_Cmd(ENABLE);
   LPC_CounterCmd(ENABLE);
}

LPC comparator function interrupt handle flow is shown in the figure below.

LPC Comparator Function Interrupt Handle Flow Chart

The codes below demonstrate the LPC comparator function interrupt handle flow.

void lpc_rtc_handler(void)
{
   uint16_t lpc_counter_value = 0;

   IO_PRINT_INFO0("lpc_rtc_handler");

   /* LPC counter comparator interrupt */
   if (LPC_GetINTStatus(LPC_INT_COUNT_COMP) == SET)
   {
      lpc_counter_value = LPC_ReadCounter();
      IO_PRINT_INFO1("lpc_rtc_handler: lpc_counter_value %d", lpc_counter_value);

      LPC_WriteComparator(lpc_counter_value + LPC_COMP_VALUE);
      LPC_ClearINTPendingBit(LPC_INT_COUNT_COMP);
   }
}

Voltage Detection Function Operation Flow

The codes below demonstrate the LPC voltage detection function initialization flow.

void driver_lpc_init(void)
{
   LPC_InitTypeDef LPC_InitStruct;
   LPC_StructInit(&LPC_InitStruct);
   LPC_InitStruct.LPC_Channel   = LPC_CAPTURE_PIN;
   LPC_InitStruct.LPC_Edge      = LPC_Vin_Below_Vth;
   LPC_InitStruct.LPC_Threshold = LPC_800_mV;
   LPC_Init(&LPC_InitStruct);

   LPC_CounterReset();
   LPC_WriteComparator(LPC_COMP_VALUE);
   LPC_INTConfig(LPC_INT_COUNT_COMP, ENABLE);

#if (TARGET_RTL87X3E == 1 || CONFIG_SOC_SERIES_RTL8773E == 1)
   RTC_CpuNVICEnable(ENABLE);
   RamVectorTableUpdate(RTC_VECTORn, lpc_handler);
   /* Config LPC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = RTC_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);
#else
   LPC_INTConfig(LPC_INT_VOLTAGE_COMP, ENABLE);
   RamVectorTableUpdate(LPCOMP_VECTORn, lpc_handler);
   /* Config LPC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = LPCOMP_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);
#endif

   LPC_Cmd(ENABLE);
   LPC_CounterCmd(ENABLE);
}

The codes below demonstrate the LPC voltage detection function interrupt handle flow.

void lpc_handler(void)
{
   if (LPC_GetINTStatus(LPC_INT_COUNT_COMP) == SET)
   {
      IO_PRINT_INFO1("lpc_handler: lpc_counter_value %d", LPC_ReadCounter());
      LPC_CounterReset();
      LPC_ClearINTPendingBit(LPC_INT_COUNT_COMP);//Add Application code here
      //Add Application code here
   }
}