SM89516B datasheet(25/49 Pages) SYNCMOS

25 / 49 page

SM89516B

8-Bit Micro-controller

64KB Flash

& 1KB RAM embedded

Specifications subject to change without notice contact your sales representatives for the most recent information.

ISSFD-M087

Ver D SM89516B 08/07/2015

- 25 -

Timer 0 and Timer 1

The SM89516B has three 16-bit timer/counter registers: Timer 0, Timer 1 and Timer 2. All can be configured for

counter or timer operations.

In timer mode, the Timer 0 register or Timer 1 register is incremented every machine cycles, due to 12 oscillator

periods in a machine cycle, the count rate is 1/12 of the oscillator frequency.

In counter mode, the register is incremented when the falling edge is observed at the corresponding input pin T0 or

T1. Since it takes 2 machine cycles to recognize a 1-to-0 event, the maximum input count rate is 1/2 of the

oscillator frequency. There are no restrictions on the duty cycle, however to ensure proper recognition of 0 or 1

state, an input should be stable for at least 1 machine cycle.

Four operating modes can be selected for Timer 0 and Timer 1. Two Special Function registers (TMOD and TCON)

are used to select the appropriate mode.

Mnemonic

Description

Dir.

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

RST

Timer 0 and 1

TL0

Timer 0 , low byte

8Ah

TL0[7:0]

00H

TH0

Timer 0 , high byte

8Ch

TH0[7:0]

00H

TL1

Timer 1 , low byte

8Bh

TL1[7:0]

00H

TH1

Timer 1 , high byte

8Dh

TH1[7:0]

00H

TMOD

Timer Mode Control

89h

GATE

C/T

GATE

C/T

00H

TCON

Timer/Counter

Control

88h

TF1

TR1

TF0

TR0

IE1

IT1

IE0

IT0

00H

6.1

Timer/counter mode control register (TMOD)

Mnemonic: TMOD

Address: 89h

Reset

GATE

C/T

GATE

C/T

00h

Timer 1

Timer 0

GATE: If set, enables external gate control (pin INT0 or INT1 for Counter 0 or 1,

respectively). When INT0 or INT1 is high, and TRx bit is set (see TCON

C/T: Selects Timer or Counter operation. When set to 1, a counter operation is

performed, when cleared to 0, the corresponding register will function as a

timer.

Mode

Function

Mode0

13-bit counter/timer, with 5 lower bits in TL0 or

TL1 register and 8 bits in TH0 or TH1 register

(for Timer 0 and Timer 1, respectively). The 3

high order bits of TL0 and TL1 are hold at

zero.

Mode1

16-bit counter/timer.

Mode2

8-bit auto-reload counter/timer. The reload

value is kept in TH0 or TH1, while TL0 or TL1

is incremented every machine cycle. When

TLx overflows, a value from THx is copied to

TLx.

SM89516B Datasheet(PDF) 25 Page - SyncMOS Technologies,Inc

SM89516B Datasheet(HTML) 25 Page - SyncMOS Technologies,Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Datasheet Download

Link URL