Difference between revisions of "LPC1768: Led Blinking"

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The Below registers will be used for Configuring and using the GPIOs registers for sending and receiving the Digital signals.
 
The Below registers will be used for Configuring and using the GPIOs registers for sending and receiving the Digital signals.
 
A structure LPC_GPIOn(n= 0,1,2,3) contains all the registers for required for GPIO operation. Refer lpc17xx.h file for more info on the registers.
 
A structure LPC_GPIOn(n= 0,1,2,3) contains all the registers for required for GPIO operation. Refer lpc17xx.h file for more info on the registers.
 +
 +
 +
==LPC 1768 Pin Functions==
 +
{| class="wikitable" style="text-align:center; background-color:#ABCDEF;margin: 1em auto 1em auto"
 +
!Port Pin|| Pin Number || PINSEL_FUNC_0 || PINSEL_FUNC_1 ||PINSEL_FUNC_2 ||PINSEL_FUNC_3
 +
|-
 +
|P0.00 || 46 || GPIO || CAN1_Rx || TXD3 || SDA1
 +
|-
 +
|P0.01 || 47 || GPIO || CAN1_Tx || RXD3 || SCL1
 +
|-
 +
|P0.02 || 98 || GPIO || TXD0 || ADC0[7] ||
 +
|-
 +
|P0.03 || 99 || GPIO || RXD0 || ADC0[6] ||
 +
|-
 +
|P0.04 || 81 || GPIO || I2SRx_CLK || CAN2_Rx || CAP2[0]
 +
|-
 +
|P0.05 || 80 || GPIO || I2SRx_Ws || CAN2_Tx || CAP2[1]
 +
|-
 +
|P0.06 || 79 || GPIO || I2SRx_SDA || SSEL1 || MAT2[0]
 +
|-
 +
|P0.07 || 78 || GPIO || I2STx_CLK || SCK1 || MAT2[1]
 +
|-
 +
|P0.08 || 77 || GPIO || I2STx_Ws || MISO1 || MAT2[2]
 +
|-
 +
|P0.09 || 76 || GPIO || I2STX_SDA || MOSI1 ||  MAT2[3]
 +
|-
 +
|P0.10 || 48 || GPIO || TXD2 || SDA2 || MAT3[0]
 +
|-
 +
|P0.11 || 49 || GPIO || RXD2 || SCL2 || MAT3[1]
 +
|-
 +
|P0.15 || 62 || GPIO || TXD1 || SCK0 || SCK
 +
|-
 +
|P0.16 || 63 || GPIO || RXD1 || SSEL0 || SSEL
 +
|-
 +
|P0.17 || 61 || GPIO || CTS1 || CTS1 || MISO
 +
|-
 +
|P0.18 || 60 || GPIO || DCD1 || MOSI0 || MOSI
 +
|-
 +
|P0.19 || 59 || GPIO || DSR1 || SDA1 ||
 +
|-
 +
|P0.20 || 58 || GPIO || DTR1 || SCL1 ||
 +
|-
 +
|P0.21 || 57 || GPIO || RI1 || RD1 ||
 +
|-
 +
|P0.22 || 56 || GPIO || RTS1 || TD1 ||
 +
|-
 +
|P0.23 || 9 || GPIO || AD0[0] || I2SRX_CLK || CAP3[0]
 +
|-
 +
|P0.24 || 8 || GPIO || AD0[1] || I2SRX_WS || CAP3[1]
 +
|-
 +
|P0.25 || 7 || GPIO || AD0[2] || I2SRX_SDA || TXD3
 +
|-
 +
|P0.26 || 6 || GPIO || AD0[3] || AOUT || RXD3
 +
|-
 +
|P0.27 || 25 || GPIO || SDA0 || USB_SDA ||
 +
|-
 +
|P0.28 || 24 || GPIO || SCL0 || USB_SCL ||
 +
|-
 +
|P0.29 || 29 || GPIO || USB_D+ ||  ||
 +
|-
 +
|P0.30 || 30 || GPIO || USB_D? ||  ||
 +
|-
 +
|p1.00 || 95 || GPIO || ENET_TXD0 ||  ||
 +
|-
 +
|p1.01 || 94 || GPIO || ENET_TXD1 ||  ||
 +
|-
 +
|p1.04 || 93 || GPIO || ENET_TX_EN ||  ||
 +
|-
 +
|p1.08 || 92 || GPIO || ENET_CRS ||  ||
 +
|-
 +
|p1.09 || 91 || GPIO || ENET_RXD0 ||  ||
 +
|-
 +
|p1.10 || 90 || GPIO || ENET_RXD1 ||  ||
 +
|-
 +
|p1.14 || 89 || GPIO || ENET_RX_ER ||  ||
 +
|-
 +
|p1.15 || 88 || GPIO || ENET_REF_CLK ||  ||
 +
|-
 +
|p1.16 || 87 || GPIO || ENET_MDC ||  ||
 +
|-
 +
|p1.17 || 86 || GPIO || ENET_MDIO ||  ||
 +
|-
 +
|p1.18 || 32 || GPIO || USB_UP_LED || PWM1[1] / CAP1[0] ||
 +
|-
 +
|p1.19 || 33 || GPIO || MCOA0 || USB_PPWR || CAP1[1]
 +
|-
 +
|p1.20 || 34 || GPIO || MCI0 || PWM1[2] || SCK0
 +
|-
 +
|p1.21 || 35 || GPIO || MCABORT || MCABORT || SSEL0
 +
|-
 +
|p1.22 || 36 || GPIO || MCOB0 || USB_PWRD || MAT1[0]
 +
|-
 +
|p1.23 || 37 || GPIO || MCI1 || PWM1[4] || MISO0
 +
|-
 +
|p1.24 || 38 || GPIO || MCI2 || PWM1[5] || MOSI0
 +
|-
 +
|p1.25 || 39 || GPIO || MCOA1 || MAT1[1] ||
 +
|-
 +
|p1.26 || 40 || GPIO || MCOB1 || PWM1[6] || CAP0[0]
 +
|-
 +
|p1.27 || 43 || GPIO || CLKOUT || USB_OVRCR / || CAP0[1]
 +
|-
 +
|p1.28 || 44 || GPIO || MCOA2 || PCAP1[0] || MAT0[0]
 +
|-
 +
|p1.29 || 45 || GPIO || MCOB2 || PCAP1[1] / || MAT0[1]
 +
|-
 +
|p1.30 || 21 || GPIO || VBUS || AD0[4] ||
 +
|-
 +
|p1.31 || 20 || GPIO || SCK1 || AD0[5] ||
 +
|-
 +
|p2.00 || 75 || GPIO || PWM1[1] || TXD1 ||
 +
|-
 +
|p2.01 || 74 || GPIO || PWM1[2] || RXD1 ||
 +
|-
 +
|p2.02 || 73 || GPIO || PWM1[3] || CTS1 || TRACEDATA[3]
 +
|-
 +
|p2.03 || 70 || GPIO || PWM1[4] || DCD1 || TRACEDATA[2]
 +
|-
 +
|p2.04 || 69 || GPIO || PWM1[5] || DSR1 || TRACEDATA[1]
 +
|-
 +
|p2.05 || 68 || GPIO || PWM1[6] || DTR1 || TRACEDATA[0]
 +
|-
 +
|p2.06 || 67 || GPIO || PCAP1[0] || RI1 || TRACECLK
 +
|-
 +
|p2.07 || 66 || GPIO || RD2 || RTS1 ||
 +
|-
 +
|p2.08 || 65 || GPIO || TD2 || TXD2 || ENET_MDC
 +
|-
 +
|p2.09 || 64 || GPIO || USB_CONNECT || RXD2 || ENET_MDIO
 +
|-
 +
|p2.10 || 53 || GPIO || EINT0 || NMI ||
 +
|-
 +
|p2.11 || 52 || GPIO || EINT1 || I2STX_CLK ||
 +
|-
 +
|p2.12 || 51 || GPIO || EINT2 || I2STX_WS ||
 +
|-
 +
|p2.13 || 50 || GPIO || EINT3 || I2STX_SDA ||
 +
|-
 +
|p3.25 || 27 || GPIO || MAT0[0] || PWM1[2] ||
 +
|-
 +
|p3.26 || 26 || GPIO || STCLK || MAT0[1] || PWM1[3]
 +
|-
 +
|p4.28 || 82 || GPIO || RX_MCLK || MAT2[0] || TXD3
 +
|-
 +
|p4.29 || 85 || GPIO || TX_MCLK || MAT2[1] || RXD3
 +
|}
 +
  
  

Revision as of 12:45, 30 May 2015


Objective

This is first example on LPC1768 where we start with blinking the LEDs. In this tutorials we are going to discuss how to configure the LPC1768 ports for GPIO and then to use to send a low/high signal on it. Lets start blinking with LEDs and then generate the different patterns using the available LEDs.



Register Configuration

As all the LPC1768 SFRs(Special Function Registers) are defined in lpc17xx.h, this has to be included at the beginning of our project/code.

LPC1768 has its GPIOs divided into five ports PORT0 - PORT4, although many of them are not physically 32bit wide. Refer the data sheet for more info. The Below registers will be used for Configuring and using the GPIOs registers for sending and receiving the Digital signals. A structure LPC_GPIOn(n= 0,1,2,3) contains all the registers for required for GPIO operation. Refer lpc17xx.h file for more info on the registers.


LPC 1768 Pin Functions

Port Pin Pin Number PINSEL_FUNC_0 PINSEL_FUNC_1 PINSEL_FUNC_2 PINSEL_FUNC_3
P0.00 46 GPIO CAN1_Rx TXD3 SDA1
P0.01 47 GPIO CAN1_Tx RXD3 SCL1
P0.02 98 GPIO TXD0 ADC0[7]
P0.03 99 GPIO RXD0 ADC0[6]
P0.04 81 GPIO I2SRx_CLK CAN2_Rx CAP2[0]
P0.05 80 GPIO I2SRx_Ws CAN2_Tx CAP2[1]
P0.06 79 GPIO I2SRx_SDA SSEL1 MAT2[0]
P0.07 78 GPIO I2STx_CLK SCK1 MAT2[1]
P0.08 77 GPIO I2STx_Ws MISO1 MAT2[2]
P0.09 76 GPIO I2STX_SDA MOSI1 MAT2[3]
P0.10 48 GPIO TXD2 SDA2 MAT3[0]
P0.11 49 GPIO RXD2 SCL2 MAT3[1]
P0.15 62 GPIO TXD1 SCK0 SCK
P0.16 63 GPIO RXD1 SSEL0 SSEL
P0.17 61 GPIO CTS1 CTS1 MISO
P0.18 60 GPIO DCD1 MOSI0 MOSI
P0.19 59 GPIO DSR1 SDA1
P0.20 58 GPIO DTR1 SCL1
P0.21 57 GPIO RI1 RD1
P0.22 56 GPIO RTS1 TD1
P0.23 9 GPIO AD0[0] I2SRX_CLK CAP3[0]
P0.24 8 GPIO AD0[1] I2SRX_WS CAP3[1]
P0.25 7 GPIO AD0[2] I2SRX_SDA TXD3
P0.26 6 GPIO AD0[3] AOUT RXD3
P0.27 25 GPIO SDA0 USB_SDA
P0.28 24 GPIO SCL0 USB_SCL
P0.29 29 GPIO USB_D+
P0.30 30 GPIO USB_D?
p1.00 95 GPIO ENET_TXD0
p1.01 94 GPIO ENET_TXD1
p1.04 93 GPIO ENET_TX_EN
p1.08 92 GPIO ENET_CRS
p1.09 91 GPIO ENET_RXD0
p1.10 90 GPIO ENET_RXD1
p1.14 89 GPIO ENET_RX_ER
p1.15 88 GPIO ENET_REF_CLK
p1.16 87 GPIO ENET_MDC
p1.17 86 GPIO ENET_MDIO
p1.18 32 GPIO USB_UP_LED PWM1[1] / CAP1[0]
p1.19 33 GPIO MCOA0 USB_PPWR CAP1[1]
p1.20 34 GPIO MCI0 PWM1[2] SCK0
p1.21 35 GPIO MCABORT MCABORT SSEL0
p1.22 36 GPIO MCOB0 USB_PWRD MAT1[0]
p1.23 37 GPIO MCI1 PWM1[4] MISO0
p1.24 38 GPIO MCI2 PWM1[5] MOSI0
p1.25 39 GPIO MCOA1 MAT1[1]
p1.26 40 GPIO MCOB1 PWM1[6] CAP0[0]
p1.27 43 GPIO CLKOUT USB_OVRCR / CAP0[1]
p1.28 44 GPIO MCOA2 PCAP1[0] MAT0[0]
p1.29 45 GPIO MCOB2 PCAP1[1] / MAT0[1]
p1.30 21 GPIO VBUS AD0[4]
p1.31 20 GPIO SCK1 AD0[5]
p2.00 75 GPIO PWM1[1] TXD1
p2.01 74 GPIO PWM1[2] RXD1
p2.02 73 GPIO PWM1[3] CTS1 TRACEDATA[3]
p2.03 70 GPIO PWM1[4] DCD1 TRACEDATA[2]
p2.04 69 GPIO PWM1[5] DSR1 TRACEDATA[1]
p2.05 68 GPIO PWM1[6] DTR1 TRACEDATA[0]
p2.06 67 GPIO PCAP1[0] RI1 TRACECLK
p2.07 66 GPIO RD2 RTS1
p2.08 65 GPIO TD2 TXD2 ENET_MDC
p2.09 64 GPIO USB_CONNECT RXD2 ENET_MDIO
p2.10 53 GPIO EINT0 NMI
p2.11 52 GPIO EINT1 I2STX_CLK
p2.12 51 GPIO EINT2 I2STX_WS
p2.13 50 GPIO EINT3 I2STX_SDA
p3.25 27 GPIO MAT0[0] PWM1[2]
p3.26 26 GPIO STCLK MAT0[1] PWM1[3]
p4.28 82 GPIO RX_MCLK MAT2[0] TXD3
p4.29 85 GPIO TX_MCLK MAT2[1] RXD3


PINSEL: GPIO Pins Select Register
Almost all the LPC1768 pins are multiplexed to support more than 1 function. Every GPIO pin has a minimum of one function and max of four functions. The required function can be selected by configuring the PINSEL register. As there can be up to 4 functions associated with a GPIO pin, two bits for each pin are available to select the function. This implies that we need two PINSEL registers to configure a PORT pins. By this the first 16(P0.0-P0.16) pin functions of PORT0 can be selected by 32 bits of PINSELO register. The remaining 16 bits(P0.16-P0.32) are configured using 32bits of PINSEL1 register. As mentioned earlier every pin has max of four functions. Below table shows how to select the function for a particular pin using two bits of the PINSEL register.

Value Function Enumeration
00 Primary (default) function, typically GPIO port PINSEL_FUNC_0
01 First alternate function PINSEL_FUNC_1
10 Second alternate function PINSEL_FUNC_2
11 Third alternate function PINSEL_FUNC_3


FIODIR:Fast GPIO Direction Control Register.
This register individually controls the direction of each port pin.

Values Direction
0 Input
1 Output


FIOSET:Fast Port Output Set Register.
This register controls the state of output pins. Writing 1s produces highs at the corresponding port pins. Writing 0s has no effect. Reading this register returns the current contents of the port output register not the physical port value.

Values FIOSET
0 No Effect
1 Sets High on Pin


FIOCLR:Fast Port Output Clear Register.
This register controls the state of output pins. Writing 1s produces lows at the corresponding port pins. Writing 0s has no effect.

Values FIOCLR
0 No Effect
1 Sets Low on Pin



FIOPIN:Fast Port Pin Value Register.
This register is used for both reading and writing data from/to the PORT.
Output: Writing to this register places corresponding values in all bits of the particular PORT pins.
Input: The current state of digital port pins can be read from this register, regardless of pin direction or alternate function selection (as long as pins are not configured as an input to ADC).
Note:It is recommended to configure the PORT direction and pin function before using it.

Schematic

Example1

Program to demonstrate the LED blinking.
Here first the PORT2 pins are selected for GPIO using PINSEL register then they are configured as Output using the FIODIR register.
LEDs are turned ON by sending a high pulse using FIOSET register.
After some time the LEDs are turned OFF by sending the low pulse using FIOCLR register.

Example2

This is second approach in which FIOPIN register is used for both setting and clearing the PORT pins.
Writing Logic 1 will set the PORT pin and writing 0 will Clear the particular PORT bit.

Using Explore Embedded Libraries:

In the above tutorial we just discussed how to configure the PORTS for GPIO for blinking the Leds.
Once you know the GPIO configurations, you can directly use the ExploreEmbedded libraries to play around with LEDs.
For that you need to include the gpio.c/gpio.h and the associated files(delay/stdutils).
The below sample code shows how to use the GPIO functions.

Refer this link for more info on GPIO libraries.

Downloads

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