Register Descriptions

27.6.6.2QADC Status Register 1 (QASR1)

Stop mode resets this register .

Field

Reset

R/W:

Field

Reset

R/W: Address

15

14

13

12

11

10

9

8

 

 

CWPQ15

 

CWPQ14

 

 

CWPQ13

 

CWPQ12

CWPQ11

CWPQ10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0011_1111

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CWPQ25

 

CWPQ24

 

 

CWPQ23

 

CWPQ22

CWPQ21

CWPQ20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0011_1111

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

 

IPSBAR + 0x19_0012, 0x19_0013

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 27-13. QADC Status Register 1 (QASR1)

Table 27-13. QASR1 Field Descriptions

Bit(s)

Name

Description

 

 

 

15–14

Reserved, should be cleared.

 

 

 

13–8

CWPQ1

Queue 1 command word pointer. Points to the last queue 1 CCW executed. This is a read-only

 

 

field with a valid range of 0 to 63; writes have no effect. CWPQ1 always points to the last

 

 

executed CCW in queue 1, regardless of which queue is active.

 

 

In contrast to CWP, CPWQ1 is updated when a conversion result is written. When the QADC

 

 

finishes a conversion in queue 1, both the result register is written and CWPQ1 is updated.

 

 

When queue 1 operation is terminated after a CCW is read that is pointed to by BQ2, CWP

 

 

points to BQ2 while CWPQ1 points to the last queue 1 CCW.

 

 

During stop mode, CWPQ1 is reset to 63, because the control registers and the analog logic are

 

 

reset. When debug mode is entered, CWPQ1 is not changed; it points to the last executed CCW

 

 

in queue 1.

 

 

 

7–6

Reserved, should be cleared.

 

 

 

5–0

CWPQ

Queue 2 command word pointer. Points to the last queue 2 CCW executed. This is a read-only

 

 

field with a valid range of 0 to 63; writes have no effect. CWPQ2 always points to the last

 

 

executed CCW in queue 2, regardless which queue is active.

 

 

In contrast to CWP, CPWQ2 is updated when a conversion result is written. When the QADC

 

 

finishes a conversion in queue 2, both the result register is written and CWPQ2 is updated.

 

 

During stop mode, CWPQ2 is reset to 63 because the control registers and the analog logic are

 

 

reset. When debug mode is entered, CWPQ2 is not changed; it points to the last executed CCW

 

 

in queue 2.

 

 

 

27.6.7 Conversion Command Word Table (CCW)

The CCW table is 64 half-word (128 byte) long RAM with 10 bits of each entry implemented. The CCW table is written by the user and is not modified by the QADC. Each CCW requests the conversion of one analog channel to a digital result. The CCW specifies the analog channel number, the input sample time, and whether the queue is to pause after

27-26

MCF5282 User’s Manual

MOTOROLA

Page 610
Image 610
Motorola MCF5282, MCF5281 user manual Conversion Command Word Table CCW, Qadc Status Register 1 QASR1