The following table summarizes Timer A’s capabilities.

 

Table 11-2.

Timer A Capabilities

 

 

 

 

 

Timer

Cascade

 

Interrupt

Dedicated Connection

 

 

 

 

 

A1

none

 

yes

Parallel Ports D-G, Timer B

 

 

 

 

 

A2

from A1

 

yes

Serial Port E

 

 

 

 

 

A3

from A1

 

yes

Serial Port F

 

 

 

 

 

A4

from A1

 

yes

Serial Port A

 

 

 

 

 

A5

from A1

 

yes

Serial Port B

 

 

 

 

 

A6

from A1

 

yes

Serial Port C

 

 

 

 

 

A7

from A1

 

yes

Serial Port D

 

 

 

 

 

A8

none

 

no

Input Capture

 

 

 

 

 

A9

none

 

no

Pulse Width Modulator

 

 

 

 

 

A10

none

 

no

Quadrature Decoder

 

 

 

 

 

The control/status register for Timer A (TACSR) is laid out as shown in Table 11-3.

Table 11-3. Timer A Control and Status Register

Timer A Control and Status Register

(TACSR)

(Address = 0x00A0)

 

 

 

 

 

Bit(s)

Value

 

Description

 

 

 

 

 

7

0

A7 counter has not reached its terminal count.

 

 

 

 

 

(read)

1

A7 count done. This status bit is cleared by a read of this register.

 

 

 

 

 

 

7

0

A7 interrupt disabled.

 

 

 

 

 

 

(write)

1

A7 interrupt enabled.

 

 

 

 

 

 

 

 

 

6

0

A6 counter has not reached its terminal count.

 

 

 

 

 

(read)

1

A6 count done. This status bit is cleared by a read of this register.

 

 

 

 

 

 

6

0

A6 interrupt disabled.

 

 

 

 

 

 

(write)

1

A6 interrupt enabled.

 

 

 

 

 

 

 

 

 

5

0

A5 counter has not reached its terminal count.

 

 

 

 

 

(read)

1

A5 count done. This status bit is cleared by a read of this register.

 

 

 

 

 

 

5

0

A5 interrupt disabled.

 

 

 

 

 

 

(write)

1

A5 interrupt enabled.

 

 

 

 

 

 

 

 

 

4

0

A4 counter has not reached its terminal count.

 

 

 

 

 

(read)

 

 

 

 

1

A4 count done. This status bit is cleared by a read of this register.

 

 

 

 

 

 

 

 

 

 

 

152

Rabbit 3000 Microprocessor

Page 161
Image 161
Jameco Electronics 2000, 3000 manual Timer a Capabilities, Timer a Control and Status Register, Tacsr