Файл: Embedded system development and labs for ARM (R. Muresan, 2005).pdf

Embedded Systems Development and Labs; The English Edition

bit is 0/1, the pull-up resistor of the pin is enabled/disabled.

(4) External Interrupt Control Register

The 8 external interrupts are activated through various signaling methods that are programmed in the EXTINT register. The signaling methods available are: low level trigger, high level trigger, falling edge trigger, rising edge trigger, and both edge triggers for the external interrupt request

Table 4-12 to Table 4-18 show the pin definitions of each port.

Table 4-12 Port A

PCONA access address: 0X01D20000

PDATA access address: 0X01D20004

PCONA reset value: 0X1FF

Table 4-13 Port B

PCONB access address: 0X01D20008

PDATB access address: 0X01D2000C

PCONB reset value: 0X7FF

Table 4-14 Port C

PCONC access address: 0X01D20010

PDATC access address: 0X01D20014

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PUPC access address: 0X01D20018

PCONC reset value: 0X0FF0FFFF

Table 4-15 Port D

PCOND access address: 0X01D2001C

PDATD access address: 0X01D20020

PUPD access address: 0X01D20024

PCOND reset value: 0XAAAA

Table 4-16 Port E

PCONE access address: 0X01D20028

PDATE access address: 0X01D2002C

PUPE access address: 0X01D20030

PCONE reset value: 0X25529

Table 4-17 Port F

PCONF access address: 0X01D20034

PDATF access address: 0X01D20038

PUPF access address: 0X01D2003C

PCONF reset value: 0X00252A

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Embedded Systems Development and Labs; The English Edition

Table 4-18 Port G

PCONG access address: 0X01D20040

PDATG access address: 0X01D20044

PUPG access address: 0X01D20048

PCONG reset value: 0XFFFF

2. The Description of the Circuit

In Table 4-13 PB9 and PB10 pins are defined as outputs and are connected to LED1 and LED2. Figure 4-5 shows the circuit connections for the LED1 and LED2. The anodes of LED1 and LED2 are connected to the pin 47 of S3C44B0X which is VDD33. VDD33 pin provides a 3.3V dc voltage. The cathodes of LED1 and LED2 are connected to pin 23 (PB9) and 24 (PB10), respectively. These two pins belong to Port B and have been configured as outputs. Writing a 1 or a 0 to the specific bit of the PDATAB register can make the pin’s output low or high. When the pin 23, 24 is low, the LEDs will be on (lit). When the pin 23, 24 is high, the LEDs will be off.

Figure 4-5. Connection diagram to LED 1 and LED 2

4.2.5 Operation Steps

1)Prepare the Lab environment. Connect the Embest Emulator to the target board. Connect the target board UART0 to the PC serial port through the serial cable provided by the Embest development system.

2)Run the PC Hyper Terminal (set to 115200 bits per second, 8 data bits, none parity, 1 stop bits, none flow control).

3)Connect the Embest Emulator to the target board. Open the LED_test.ews project file that is located in the …\EmbestIDE\Examples\Samsung\S3CEV40 directory. Compile and link the project. Connect to the target

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Embedded Systems Development and Labs; The English Edition

board and download the program.

NOTE: please note that the debug window should be set as in Figure 4-5a:

Figure 4-5a. Debug settings for the project

4)Watch the hyper terminal output. The following should be displayed: Embest 44B0X Evaluation Board (S3CEV40)

LED Test Example

5)The LED1 and LED2 will be in the following states:

LED1 on Æ LED2 on Æ LED1 and LED2 onÆ LED2 off Æ LED1 off.

4.2.6 Sample Programs

/*****************************************************************************

*File Name: light.c

*Author: embest

*Description: control board's two LEDs on or offf

*History:

*****************************************************************************/

/*--- include files ---*/ #include "44b.h" #include "44blib.h"

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/*--- function code---*/ /*************************************************************************

*modify:

*comment:

**************************************************************************/

void Led_Test()

{

/* 1 on -> 2 on -> all on -> 2 off -> 1 off */ leds_off();

Delay(1000); led1_on(); Delay(1000); led1_off(); led2_on(); Delay(1000); leds_on(); Delay(1000); led2_off(); Delay(1000); led1_off();

}

/***************************************************************************

*modify:

*comment:

***************************************************************************/

void leds_on()

{

Led_Display(0x3);

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