The GPIO of LPC1125 cannot output low level, why?

Wei_Lang — Wed, 13 Mar 2024 07:34:54 GMT

The GPIO of the LPC1125 cannot output low level, why?

main();

int main (void) { SystemCoreClockUpdate();//LPC1125 Clock Settings. LPC1125时钟设置 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 6 | 1UL << 16); /* enable clock for GPIO */ LPC_IOCON->PIO2_0 = 0xD0; LPC_IOCON->PIO2_1 = 0xD0; LPC_IOCON->PIO2_2 = 0xD0; LPC_GPIO2->DIR = 0x07; LPC_GPIO2->MASKED_ACCESS[0x07] = 0; //However, PIO2_0 is always high, and cannot output low level. The program downloads normally. //但是PIO2_0始终是高电平，无法输出低电平。程序下载正常。 }

SystemCoreClockUpdate();

void SystemCoreClockUpdate (void) /* Get Core Clock Frequency */ { uint32_t oscClk = 0; /* Determine clock frequency according to clock register values */ switch ((LPC_SYSCON->WDTOSCCTRL >> 5) & 0x0F) { case 0: oscClk = 0; break; case 1: oscClk = 600000; break; case 2: oscClk = 1050000; break; case 3: oscClk = 1400000; break; case 4: oscClk = 1750000; break; case 5: oscClk = 2100000; break; case 6: oscClk = 2400000; break; case 7: oscClk = 2700000; break; case 8: oscClk = 3000000; break; case 9: oscClk = 3250000; break; case 10: oscClk = 3500000; break; case 11: oscClk = 3750000; break; case 12: oscClk = 4000000; break; case 13: oscClk = 4200000; break; case 14: oscClk = 4400000; break; case 15: oscClk = 4600000; break; } oscClk /= ((LPC_SYSCON->WDTOSCCTRL & 0x1F) << 1) + 2; switch (LPC_SYSCON->MAINCLKSEL & 0x03) { case 0: /* Internal RC oscillator */ SystemCoreClock = __IRC_OSC_CLK; break; case 1: /* Input Clock to System PLL */ switch (LPC_SYSCON->SYSPLLCLKSEL & 0x03) { case 0: /* Internal RC oscillator */ SystemCoreClock = __IRC_OSC_CLK; break; case 1: /* System oscillator */ SystemCoreClock = __SYS_OSC_CLK; break; case 2: /* Reserved */ case 3: /* Reserved */ SystemCoreClock = 0; break; } break; case 2: /* WDT Oscillator */ SystemCoreClock = oscClk; break; case 3: /* System PLL Clock Out */ switch (LPC_SYSCON->SYSPLLCLKSEL & 0x03) { case 0: /* Internal RC oscillator */ if (LPC_SYSCON->SYSPLLCTRL & 0x180) { SystemCoreClock = __IRC_OSC_CLK; } else { SystemCoreClock = __IRC_OSC_CLK * ((LPC_SYSCON->SYSPLLCTRL & 0x01F) + 1); } break; case 1: /* System oscillator */ if (LPC_SYSCON->SYSPLLCTRL & 0x180) { SystemCoreClock = __SYS_OSC_CLK; } else { SystemCoreClock = __SYS_OSC_CLK * ((LPC_SYSCON->SYSPLLCTRL & 0x01F) + 1); } break; case 2: /* Reserved */ case 3: /* Reserved */ SystemCoreClock = 0; break; } break; } SystemCoreClock /= LPC_SYSCON->SYSAHBCLKDIV; }

SYSAHBCLKCTR

SYSAHBCLKCTRL bit Symbol Value Description 6 GPIO 0 Disable clock for GPIO. 1 Enable * 16 IOCON 0 Disable clock for I/O configuration block. 1 Enable *

LPC_GPIO2->DIR

LPC_GPIO2->MASKED_ACCESS

/*------------- General Purpose Input/Output (GPIO) --------------------------*/ /** @addtogroup LPC112x_GPIO LPC112x General Purpose Input/Output @{ */ typedef struct { union { __IO uint32_t MASKED_ACCESS[4096]; /*!< Offset: 0x0000 to 0x3FFC Port data Register for pins PIOn_0 to PIOn_11 (R/W) */ struct { uint32_t RESERVED0[4095]; __IO uint32_t DATA; /*!< Offset: 0x3FFC Port data Register (R/W) */ }; }; uint32_t RESERVED1[4096]; __IO uint32_t DIR; /*!< Offset: 0x8000 Data direction Register (R/W) */ __IO uint32_t IS; /*!< Offset: 0x8004 Interrupt sense Register (R/W) */ __IO uint32_t IBE; /*!< Offset: 0x8008 Interrupt both edges Register (R/W) */ __IO uint32_t IEV; /*!< Offset: 0x800C Interrupt event Register (R/W) */ __IO uint32_t IE; /*!< Offset: 0x8010 Interrupt mask Register (R/W) */ __I uint32_t RIS; /*!< Offset: 0x8014 Raw interrupt status Register (R/ ) */ __I uint32_t MIS; /*!< Offset: 0x8018 Masked interrupt status Register (R/ ) */ __O uint32_t IC; /*!< Offset: 0x801C Interrupt clear Register (/W) */ } LPC_GPIO_TypeDef;

//However, PIO2_0 is always high, and cannot output low level. The program downloads normally.
//但是PIO2_0始终是高电平，无法输出低电平。程序下载正常。

Re: The GPIO of LPC1125 cannot output low level, why?

xiangjun_rong — Wed, 13 Mar 2024 09:45:23 GMT

Hi,

Just after a brief review, can you use the code and test the pin:

change

LPC_GPIO2->MASKED_ACCESS[0x07] = 0;

LPC_GPIO2->MASKED_ACCESS[4095] = 0;

Pls have a try

XiangJun Rong

Re: The GPIO of LPC1125 cannot output low level, why?

Wei_Lang — Thu, 14 Mar 2024 02:28:16 GMT

It cannot solve when I changing to :

LPC_GPIO2->MASKED_ACCESS[4095] = 0;

There may be other problems.

Re: The GPIO of LPC1125 cannot output low level, why?

Wei_Lang — Wed, 20 Mar 2024 08:54:25 GMT

1. SWDIO/PIO1_3, add external 4.7K to 10K pull up resistor. SWD_CLK don't add external circuit.
2. RESET/PIO0_0, should add 4.7K to 10K pull up resistor, and 0.1uf Capacitor to ground.
3. P0_1, should add 4.7K to 10K pull up resistor.
4. Check the schematic diagram and select the correct PIO2_0.

Wei Lang

topic The GPIO of LPC1125 cannot output low level, why? in LPC Microcontrollers

The GPIO of LPC1125 cannot output low level, why?

Re: The GPIO of LPC1125 cannot output low level, why?

Re: The GPIO of LPC1125 cannot output low level, why?

Re: The GPIO of LPC1125 cannot output low level, why?