C8051F310 参数 Datasheet PDF下载

C8051F310/1/2/3/4/5/6/7

17.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)

In Mode 3, Timer 0 is configured as two separate 8-bit counter/timers held in TL0 and TH0. The

counter/timer in TL0 is controlled using the Timer 0 control/status bits in TCON and TMOD: TR0, C/T0,

GATE0 and TF0. TL0 can use either the system clock or an external input signal as its timebase. The TH0

register is restricted to a timer function sourced by the system clock or prescaled clock. TH0 is enabled

using the Timer 1 run control bit TR1. TH0 sets the Timer 1 overflow flag TF1 on overflow and thus controls

the Timer 1 interrupt.

Timer 1 is inactive in Mode 3. When Timer 0 is operating in Mode 3, Timer 1 can be operated in Modes 0,

1 or 2, but cannot be clocked by external signals nor set the TF1 flag and generate an interrupt. However,

the Timer 1 overflow can be used to generate baud rates for the SMBus and/or UART, and/or initiate ADC

conversions. While Timer 0 is operating in Mode 3, Timer 1 run control is handled through its mode set-

tings. To run Timer 1 while Timer 0 is in Mode 3, set the Timer 1 Mode as 0, 1, or 2. To disable Timer 1,

configure it for Mode 3.

CKCON

T

T

T

T

T

T

S

3

3

2

2

1

0

C

M

M

M

M

M

M

A

H

L

H

L

1

S

C

A

0

G

A

T

E

1

TMOD

C

/

T

1

T

1

M

1

T

1

M

0

G

A

T

E

0

C

/

T

0

T

T

0

0

M

M

1

0

Pre-scaled Clock

0

TR1

TH0

(8 bits)

TF1

TR1

TF0

TR0

IE1

IT1

IE0

IT0

Interrupt

Interrupt

SYSCLK

1

1

T0

TL0

(8 bits)

TR0

Crossbar

GATE0

/INT0

IN0PL

XOR

Figure 17.3. T0 Mode 3 Block Diagram

190

Rev. 1.7

TCON

0