Timer0 Mode1

Macros
#define	INT0   P32
	INT0 pin definition.
#define	INT0   P32
	INT0 pin definition.
#define	INT0   P32
	INT0 pin definition.

init
Timer initializaion functions
#define	timer0_mode1_12T_init()
	Initialize mode1 12T for timer0. More...
#define	timer0_mode1_1T_init()
	Initialize mode1 1T for timer0. More...

config
Timer configuration functions
#define	timer0_mode1_close_gate()   (bit_set(TMOD, SBIT3))
	Close timer starting gate. More...
#define	timer0_mode1_open_gate()   (bit_clr(TMOD, CBIT3))
	Open timer starting gate. More...
#define	is_timer0_mode1_gate_opened()   (test_if_bit_cleared(TMOD, SBIT3))
	Get timer starting gate state. More...

run in async mode
Timer run/stop/reload functions
#define	timer0_mode1_start(ticks)
	Run timer0 in mode1. More...
#define	timer0_mode1_direct_start(th0, tl0)
	Run timer0 in mode1 with direct set of TH0 and TL0 registers. More...
#define	timer0_mode1_stop()
	Stop timer0. More...
#define	is_timer0_mode1_started()   (TR0 == 1 && (is_timer0_mode1_gate_opened() || INT0 == 1))
	Get timer0 mode1 started status. More...

run in sync mode
Timer run once functions
#define	timer0_mode1_delay(ticks)
	Run timer0 mode1 once and wait with program flow blocking timer not finished. More...

Detailed Description

Functions and data structures for timer0 mode1.

This module supports general purpose timer0. Timer can work as COUNTER or TIMER.

Counter increments on external singnal (like pin 1/0 change state).

Timer0 Mode1 is like mode0 but without timer reloading and P35 pin output features.

For timer0 in mode1:

• Input of timer is system clock.
• By default timer input is 12T mode. Timer increments by sysClock/12.
• Timer input can be switched to 1T mode. In this mode timer increments by sysClock/1.

Timer0 in mode1 can be used in sync (main prorgam flow blocked until timer overloaded) and interrupt (call interrupt handler on timer overloaded) modes.

Author

Michael Golovanov

Macro Definition Documentation

is_timer0_mode1_gate_opened

#define is_timer0_mode1_gate_opened

(

)

(test_if_bit_cleared(TMOD, SBIT3))

Get timer starting gate state.

Returns

bool true if gate is open otherwise false

is_timer0_mode1_started

#define is_timer0_mode1_started

(

)

(TR0 == 1 && (is_timer0_mode1_gate_opened() || INT0 == 1))

Get timer0 mode1 started status.

Returns

bool true if started otherwise false

timer0_mode1_12T_init

#define timer0_mode1_12T_init

(

)

Value:

{                                                       \
    enable_mcu_interrupts();                            \
    enable_timer0_interrupt();                          \
    TMOD &= 0xf0;                                       \
    bit_set(TMOD, SBIT0);                               \
    bit_clr(AUXR, CBIT7);                               \
}

Initialize mode1 12T for timer0.

timer0_mode1_1T_init

#define timer0_mode1_1T_init

(

)

Value:

{                                                       \
    enable_mcu_interrupts();                            \
    enable_timer0_interrupt();                          \
    TMOD &= 0xf0;                                       \
    bit_set(TMOD, SBIT0);                               \
    bit_set(AUXR, SBIT7);                               \
}

Initialize mode1 1T for timer0.

timer0_mode1_close_gate

#define timer0_mode1_close_gate

(

)

(bit_set(TMOD, SBIT3))

Close timer starting gate.

When gate is closed timer will ticks after start only when INT0 pin is HIGH

timer0_mode1_delay

#define timer0_mode1_delay

(

ticks

)

Value:

{                                                                       \
    bool is_gate_opened = is_timer0_mode1_gate_opened();                \
                                                                        \
    timer0_mode1_open_gate();                                           \
                                                                        \
    timer0_mode1_start(ticks);                                          \
    /* Waiting for timer overloaded (timer overload flag set to 1) */   \
    while(!TF0)                                                         \
    {                                                                   \
    }                                                                   \
    timer0_mode1_stop();                                                \
                                                                        \
    if (!is_gate_opened)                                                \
    {                                                                   \
        timer0_mode1_close_gate();                                      \
    }                                                                   \
}

Run timer0 mode1 once and wait with program flow blocking timer not finished.

Before run timer0_mode1_12T_init or timer0_mode1_1T_init should be called.

After run program flow blocked until timer does not overloaded.

Dont mix call of timer0_mode1_delay with timer0_mode1_open_gate/timer0_mode1_close_gate calls.

Parameters

ticks

uint16_t timer ticks count.

timer0_mode1_direct_start

#define timer0_mode1_direct_start	(		th0,
			tl0
	)

Value:

{                                                           \
    TH0 = th0;                                              \
    TL0 - tl0;                                              \
                                                            \
    TF0 = 0;                                                \
    TR0 = 1;                                                \
}

Run timer0 in mode1 with direct set of TH0 and TL0 registers.

Before run timer0_mode1_12T_init or timer0_mode1_1T_init should be called.

After run program flow not blocked and interrupt will raised when timer is overloaded. Interrupt handler void timer0ISR(void) __interrupt(1) should be defined in user code.

Timer rerun after overloaded and interupt handler called. Timer overload occurs on [TH0, TL0] = 0xff + 1.

Dont mix call timer0__mode1_direct_start call with void timer0_mode1_delay call

Parameters

th0	uint8_t TH0 value
tl0	uint8_t TL0 value

timer0_mode1_open_gate

#define timer0_mode1_open_gate

(

)

(bit_clr(TMOD, CBIT3))

Open timer starting gate.

When gate is open timer ticks after starts

timer0_mode1_start

#define timer0_mode1_start

(

ticks

)

Value:

{                                                           \
    uint16_t value = 0xffff - ticks;                        \
    /* Load timer high and low bytes value */               \
    TL0 = value & 0xff;                                     \
    TH0 = (value >> 8) & 0xff;                              \
                                                            \
    TF0 = 0; /* clear timer overload flag */                \
    TR0 = 1; /* set run timer flag */                       \
}

Run timer0 in mode1.

Before run timer0_mode1_12T_init or timer0_mode1_1T_init should be called.

After run program flow not blocked and interrupt will raised when timer is overloaded. Interrupt handler void timer0ISR(void) __interrupt(1) should be defined in user code.

Timer rerun after overloaded and interupt handler called.

Dont mix call timer0__mode1_start call with void timer0_mode1_delay call

Parameters

ticks

uint16_t timer ticks count.

timer0_mode1_stop

#define timer0_mode1_stop

(

)

Value:

{                                                           \
    TR0 = 0; /* clear run timer flag */                     \
    TF0 = 0; /* clear timer overload flag */                \
}

Stop timer0.

Before stop timer1_start should be called. Dont mix timer1_stop call with timer0_mode1_delay call