The control/status register for Timer B (TBCSR) is laid out as shown in Table 11-7.

Table 11-7. Timer B Control and Status Register

Timer B Control and Status Register

(TBCSR)

(Address = 0x00B0)

 

 

 

 

 

Bit(s)

Value

 

Description

 

 

 

 

 

7:3

 

These bits are always read as zero.

 

 

 

 

2

0

Timer B2 comparator has not encountered a match condition.

 

 

 

 

 

Timer B2 comparator has encountered a match condition. This status bit and the

(read)

1

 

Timer B2 interrupt (but not interrupt enable) are cleared by a read of this register.

 

 

 

 

 

 

 

2

0

Timer B2 interrupt disabled.

 

 

 

 

 

 

(write)

1

Timer B2 interrupt enabled.

 

 

 

 

 

 

 

 

1

0

Timer B1 comparator has not encountered a match condition.

 

 

 

 

 

Timer B1 comparator has encountered a match condition. This status bit and the

(read)

1

 

Timer B1 interrupt (but not interrupt enable) are cleared by a read of this register.

 

 

 

 

 

 

 

1

0

Timer B1 interrupt disabled.

 

 

 

 

 

 

(write)

1

Timer B1 interrupt enabled.

 

 

 

 

 

 

 

 

 

0

0

Disable the main clock for Timer B.

 

 

 

 

 

1

Enable the main clock for Timer B.

 

 

 

 

 

 

 

 

The control register for Timer B (TBCR) is laid out as shown in Table 11-8.

Table 11-8. Timer B Control Register

 

Timer B Control Register

(TBCR)

(Address = 0x00B1)

 

 

 

 

 

Bit(s)

Value

 

Description

 

 

 

 

7:4

 

These bits are reserved and should be written with zeroes.

 

 

 

 

00

Timer B clocked by the main Timer B clock (perclk/2).

 

 

 

 

3:2

01

Timer B clocked by the output of Timer A1.

 

 

 

 

 

1x

Timer B clocked by the main Timer B clock (perclk/2) divided by 8.

 

 

 

 

 

 

00

Timer B interrupts are disabled.

 

 

 

 

 

 

1:0

01

Timer B interrupts use Interrupt Priority 1.

 

 

 

 

 

10

Timer B interrupts use Interrupt Priority 2.

 

 

 

 

 

 

 

 

11

Timer B interrupts use Interrupt Priority 3.

 

 

 

 

 

 

User’s Manual

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Page 166
Image 166
Jameco Electronics 3000, 2000 manual Timer B Control and Status Register, Timer B Control Register, Tbcsr, Tbcr