TIMER/COUNTER UNIT

Register Name:

Register Mnemonic:

Register Function:

15

E

I

I

R

N

N

N

I

 

H

T

U

 

 

 

 

Timer 0 and 1 Control Registers

T0CON, T1CON

Defines Timer 0 and 1 operation.

 

 

 

 

 

 

 

 

0

 

 

M

R

 

P

E

A

C

 

 

C

T

 

 

X

L

O

 

 

 

G

 

 

T

T

N

 

 

 

 

 

 

 

 

T

 

 

 

 

 

 

 

 

 

A1297-0A

Bit

Bit Name

Reset

 

 

Function

Mnemonic

State

 

 

 

 

 

 

 

 

 

 

 

 

EN

Enable

0

Set to enable the timer. This bit can be written only

 

 

 

when the

INH

bit is set.

 

 

 

 

INH

Inhibit

X

Set to enable writes to the EN bit. Clear to ignore

 

 

 

writes to the EN bit. The

INH

bit is not stored; it

 

 

 

always reads as zero.

 

 

 

 

INT

Interrupt

X

Set to generate an interrupt request when the Count

 

 

 

register equals a Maximum Count register. Clear to

 

 

 

disable interrupt requests.

 

 

 

 

RIU

Register In

X

Indicates which compare register is in use. When set,

 

Use

 

the current compare register is Maxcount Compare B;

 

 

 

when clear, it is Maxcount Compare A.

 

 

 

 

MC

Maximum

X

This bit is set when the counter reaches a maximum

 

Count

 

count. The MC bit must be cleared by writing to the

 

 

 

Timer Control register. This is not done automati-

 

 

 

cally. If MC is clear, the counter has not reached a

 

 

 

maximum count.

 

 

 

 

 

 

 

 

NOTE: Reserved register bits are shown with gray shading. Reserved bits must be written to a logic zero to ensure compatibility with future Intel products.

Figure 9-5. Timer 0 and Timer 1 Control Registers

9-7

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Intel 80C188XL, 80C186XL user manual Timer 0 and 1 Control Registers, T0CON, T1CON, Defines Timer 0 and 1 operation