Register Descriptions

If BQ2[6:0] is changed while queue 1 is active, the effect of BQ2[6:0] as an end-of-queue indication for queue 1 is immediate. However, beware of the risk of losing the end-of-queue 1 when changing BQ2[6:0]. Using EOQ (channel 63) to end queue 1 is recommended.

NOTE

If BQ2[6:0] was assigned to the CCW that queue 1 is currently working on, then that conversion is completed before the change to BQ2[6:0] takes effect.

Each time a CCW is read for queue 1, the CCW location is compared with the current value of the BQ2[6:0] pointer to detect a possible end-of-queue condition. For example, if BQ2[6:0] is changed to CCW3 while queue 1 is converting CCW2, queue 1 is terminated after the conversion is completed. However, if BQ2[6:0] is changed to CCW1 while queue

1is converting CCW2, the QADC would not recognize a BQ2[6:0] end-of-queue condition until queue 1 execution reached CCW1 again, presumably on the next pass through the queue.

Stop mode resets this register (0x007f)

15

14

13

12

11

10

9

8

Field

Reset

R/W:

CIE2

PIE2

SSE2

MQ212

 

MQ211

MQ210

MQ29

MQ28

 

 

 

 

 

 

 

 

 

 

 

0000_0000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

 

 

 

 

 

 

 

 

 

 

 

7

6

5

4

3

2

1

0

Field

RESUME

BQ26

BQ25

 

BQ24

 

BQ23

 

BQ22

BQ21

BQ20

 

 

 

 

 

 

 

 

 

 

 

Reset

 

 

 

0111_1111

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W:

 

 

 

 

 

R/W

 

 

 

 

 

 

 

 

 

 

 

Address

 

 

 

IPSBAR + 0x19_000e, 0x19_000f

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 27-10. QADC Control Register 2 (QACR2)

MOTOROLA

Chapter 27. Queued Analog-to-Digital Converter (QADC)

27-17

Page 601
Image 601
Motorola MCF5281, MCF5282 user manual CIE2 PIE2 SSE2, Resume