TI CC2530 Basic Experiment (Timer 3 interrupt mode-free running)

In this experiment, the CC2530 Timer 3 (8-bit) Query method is used to control the LED1 to 1S periodic flashing, this experiment uses 2 registers T3CTL (Timer 3 control register) about Timer 3, IEN1 (interrupt enable 1 register).

For CC2530 Gpio Basics, General Gpio operation about registers, IAR Embedded Workbench IDE software use: TI CC2530 Basic Experiment (ordinary GPIO operation-Light LED)

schematic diagram :

Register Analysis :

Program :

#include <iocc2530.h>/*********************************************** * Program Description: T3 interrupt mode control LED1 with 1S of periodic flashing ********* /#define LED1 p1_0unsigned char count = 0;//used to record the number of timer overflows/*********************** * Function Description: Initialize LED1 * Note: The system does not configure the working clock using the internal RC oscillator, i.e. 16MHz *********************************  /void led1init (void) {P1sel &= ~0x01;   function: normal I/O p1dir |= 0x01;        Direction: Output LED1 = 1; Make it out of State}/*********************************** * Function Description: Timer 3 initialize **********************************/void T3init (void)              {EA = 1;       Regardless of 3,721, first turn on the total interrupt/* Enable Timer 3 Interrupt */IEN1 |= 0x08;  or t3ie = 1;      /* Enable overflow interrupt, default is enable overflow interrupt */T3ctl |= 0x08;      To view the T3CTL register, you need to enable overflow interrupt/* Set divider, free run mode */T3ctl |= 0xE0;     128 frequency T3ctl &= ~0x03;      Free Run mode/* Set Timer 3, turn on timer 3*/t3ctl |= 0x10; To view the T3CTL register, you need to start the timer}/*********************************** * Function Description: Timer 3 Interrupt handler function **********************************/# pragma vector = T3_vector__interrupt void T3_isr (void) {//ircon = 0;//clear interrupt, it seems that the hardware helps us to clear the IRCON corresponding interrupt flag bit if (++count > 254) {count = 0; LED1 =!  LED1;  }}void Main () {led1init ();  T3init (); for (;;);}

Where does the Timer 3 interrupt service program 254 come from?

The system defaults to 2 when the operating frequency is not configured, i.e. 16M=32M/2. 1/(16m/128) *n = 0.5s (once every 0.5 seconds, one off, so it looks like a 1S periodic flicker), to get N = 65200, that is, each overflow increment of (0X00~0XFF), all the total number of overflow = 65200/256 = 254.

Note: Each creation of a new project will have to configure the IAR (to do the basic experiment), TI CC2530 Basic Experiment (ordinary GPIO operation-led light) also has IAR related configuration steps

Summarize:

1, when the system does not configure the operating frequency, that is, 16M operating frequency, the timer increments each time to 1/(16000000/128) = 8us. When using free-running mode, the time required for each overflow is: 2ms

2, Timer 3 uses the interrupt mode, the initialization needs to do things: 1) Turn on the total interrupt EA = 1; 2) Enable Timer 3 interrupt 3) Enable overflow interrupt (default enable) 4) set divider, run mode 5) last start Timer 3

TI CC2530 Basic Experiment (Timer 3 interrupt mode-free running)