SOLVED - Writing and Reading the Values of an 8-bit Port with Energia

[Rei Vilo 695]

Problem solved!

 

I'd like to write and read the 8 bits of PB port on the LaunchPad Stellaris at once.

 

On the Arduino Meag2560, I can write and read the values of an 8-bit port, for example PORTC.

void LCD_HI32::_writeParallelLCD88(uint8_t dataHigh8, uint8_t dataLow8)
{
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
    PORTA = dataHigh8;
    PORTC = dataLow8;
    pulse_low(_portWR, _bitWR);
#else
//#error Platform not supported.
#endif
}

void LCD_HI32::_readParallelLCD88(uint8_t &dataHigh8, uint8_t &dataLow8)
{
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
    pulse_low(_portRS, _bitRS);
    dataHigh8 = PORTA;
    dataLow8 = PORTC;
#else
//#error Platform not supported.
#endif
}

For the MSP430, 

  uint8_t value = 2;
  P1OUT = value;
  value = P1IN;

What are the corresponding variables for Stellaris? Thank you.

[chicken 630]

For Stellaris (untested - you might need some type casting to make the compiler happy as GPIO registers are 32bit)

 

uint8_t value = 2;
GPIO_PORTB_DATA_R = value;
value = GPIO_PORTB_DATA_R;

 

The register for direction is GPIO_PORTB_DIR_R. The include file lm4f120h5qr.h defines all the registers.

[jkabat 0]

@Mention,

 

Here is what I use for my LCD driver. Note the last line.  Remember  HWREG is your friend.  A good way to do fast digital I/O.

 

//========================================// Port and bitmask used for 8-bit data bus#define LCD_DATA_PERIPH         SYSCTL_PERIPH_GPIOB#define LCD_DATA_BASE           GPIO_PORTB_BASE#define LCD_DATA_PINS           0xFF// Ports and pins used for control#define LCD_CS_PERIPH           SYSCTL_PERIPH_GPIOA#define LCD_CS_BASE             GPIO_PORTA_BASE#define LCD_CS_PIN              GPIO_PIN_7#define LCD_CD_PERIPH           SYSCTL_PERIPH_GPIOA#define LCD_CD_BASE             GPIO_PORTA_BASE#define LCD_CD_PIN              GPIO_PIN_6#define LCD_WR_PERIPH           SYSCTL_PERIPH_GPIOA#define LCD_WR_BASE             GPIO_PORTA_BASE#define LCD_WR_PIN              GPIO_PIN_5#define LCD_RD_PERIPH           SYSCTL_PERIPH_GPIOA#define LCD_RD_BASE             GPIO_PORTA_BASE#define LCD_RD_PIN              GPIO_PIN_4#define LCD_RST_PERIPH          SYSCTL_PERIPH_GPIOC#define LCD_RST_BASE            GPIO_PORTC_BASE#define LCD_RST_PIN             GPIO_PIN_7#define LCD_BKLT_PERIPH         SYSCTL_PERIPH_GPIOD#define LCD_BKLT_BASE           GPIO_PORTD_BASE#define LCD_BKLT_PIN            GPIO_PIN_6#define LCD_CS_IDLE             HWREG(LCD_CS_BASE + GPIO_O_DATA + (LCD_CS_PIN << 2)) = LCD_CS_PIN;#define LCD_CS_ACTIVE           HWREG(LCD_CS_BASE + GPIO_O_DATA + (LCD_CS_PIN << 2)) = 0;#define LCD_CD_DATA             HWREG(LCD_CD_BASE + GPIO_O_DATA + (LCD_CD_PIN << 2)) = LCD_CD_PIN;#define LCD_CD_COMMAND          HWREG(LCD_CD_BASE + GPIO_O_DATA + (LCD_CD_PIN << 2)) = 0;#define LCD_WR_IDLE             HWREG(LCD_WR_BASE + GPIO_O_DATA + (LCD_WR_PIN << 2)) = LCD_WR_PIN;#define LCD_WR_ACTIVE           HWREG(LCD_WR_BASE + GPIO_O_DATA + (LCD_WR_PIN << 2)) = 0;#define LCD_RD_IDLE             HWREG(LCD_RD_BASE + GPIO_O_DATA + (LCD_RD_PIN << 2)) = LCD_RD_PIN;#define LCD_RD_ACTIVE           HWREG(LCD_RD_BASE + GPIO_O_DATA + (LCD_RD_PIN << 2)) = 0;#define LCD_RST_IDLE            HWREG(LCD_RST_BASE + GPIO_O_DATA + (LCD_RST_PIN << 2)) = LCD_RST_PIN;#define LCD_RST_ACTIVE          HWREG(LCD_RST_BASE + GPIO_O_DATA + (LCD_RST_PIN << 2)) = 0;#define LCD_BKLT_ON             HWREG(LCD_BKLT_BASE + GPIO_O_DATA + (LCD_BKLT_PIN << 2)) = LCD_BKLT_PIN;#define LCD_BKLT_OFF            HWREG(LCD_BKLT_BASE + GPIO_O_DATA + (LCD_BKLT_PIN << 2)) = 0;#define LCD_DATA_WRITE(ucByte)  { HWREG(LCD_DATA_BASE + GPIO_O_DATA + (LCD_DATA_PINS << 2)) = (ucByte); }

 

[igor 163]

Not sure in Energia, using stellarisware you read it as

 

GPIOPinRead(GPIO_PORTB_BASE, 0xFF)

 

which translates to 

 

(HWREG( GPIO_PORTB_BASE  + (GPIO_O_DATA + (0xFF << 2))));

 

 

Edit - ignore this post, others answered while it was sitting in my browser.  Don't see a way to delete.

[chicken 630]

I usually do what @@jkabat says (looks like we used the same template for our display projects ), but thought @@Rei Vilo was looking for the straight forward version.

 

In the end, both gets compiled into the same machine code (assuming all 8 bits are read/written).

[Rei Vilo 695]

Thank you very much for the clear indications and explanations.

 

As rightly pointed by @@chicken, the following pre-processing statement is required:

#include "inc/lm4f120h5qr.h"

Without going as deep as recommended by @@jkabat, the functions mentioned by @@igor are available in Energia in the gpio.c library:

GPIODirModeSet(unsigned long ulPort, unsigned char ucPins,
               unsigned long ulPinIO)

GPIOPinWrite(unsigned long ulPort, unsigned char ucPins, unsigned char ucVal)

GPIOPinRead(unsigned long ulPort, unsigned char ucPins)

Yes, this is for a 8-bit parallel screen

[Rei Vilo 695]

On Energia, this line of code is required to have the port working fine:

GPIOPadConfigSet(GPIO_PORTB_BASE, 0xff, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD);

I can now start exploring the Kentec 3.5" display.

[Rei Vilo 695]

Here is what I use for my LCD driver. Note the last line.  Remember  HWREG is your friend.  A good way to do fast digital I/O. 

 

 

 

Thank you @@jkabat for pointing me on this interesting direction.

 

At first, I was afraid by such low-level HWREG instructions but once I get used to them, I really enjoy how fast they are!

[jkabat 0]

Glad to be of service.

 

John