Analog Devices ADSP-TS101 TigerSHARC Hardware Reference Manual page 281

When the X count becomes zero, but the Y count is nonzero, the X count
must be reloaded with the original value. The
the initial Count register while
ter holds the original count value that is restored in
The register is written automatically whenever the
DCIX
ister is loaded.
0 1 2 3
8 9 A B
10 11 12 13
18 19 1A 1B
20 21 22 23
28 29 2A 2B
30 31 32 33
38 39 3A 3B
DY COUNT
THE DY COUNT
FIELD GETS SET TO
THE NUMBER OF
ELEMENTS IN THE
Y-DIRECTION. IN
THIS CASE 0X8.
DI
THE DI REGISTER INITIALLY CONTAINS
THE FIRST ADDRESS IN THE ARRAY
AND IS UPDATED TO INDICATE THE
CURRENT ADDRESS BY ADDING THE
X INCREMENT AFTER EACH TRANSFER.
Figure 7-17. Two-Dimensional DMA of an 8x8 Array with
Quad Operand Length
ADSP-TS101 TigerSHARC Processor
Hardware Reference
TCB DX Count
4 5 6 7
C D E F
SUPPOSE WE WANT TO TRANSMIT AN 8X8 MATRIX OF DATA AS SHOWN
14 15 16 17
ON THE RIGHT WITH QUAD OPERAND TRANSFERS. WHEN MAPPED TO
1C 1D 1E 1F
MEMORY, THE VALUE 0 IS STORED IN MEMORY LOCATION 0X80100, 2 IS
STORED IN 0X80102 AND SO ON. THE MEMORY LAYOUT WOULD
24 25 26 27
EFFECTIVELY LOOK LIKE THAT SHOWN BELOW.
2C 2D 2E 2F
34 35 36 37
3C 3D 3E 3F
X-DIRECTION (ROW)
0X80138 0X80139 0X8013A
0X80130 0X80131 0X80132
0X80128 0X80129 0X8012A
0X80120 0X80121 0X80122
0X80118 0X80119 0X8011A
0X80110 0X80111 0X80112
0X80109 0X8010A
0X80108
0X80100 0X80101 0X80102
DX MODIFY
AS THE OPERAND LENGTH
IS QUAD WORD, THE DX
MODIFY FIELD IS SET TO 0X4.
Direct Memory Access
register functions as
DCIX
decrements. The
TCB DX Count
DX COUNT
THE DX COUNT FIELD GETS SET TO THE NUMBER OF
ELEMENTS IN THE X-DIRECTION. IN THIS CASE 0X8.
0X8013B 0X8013C 0X8013D
0X80133 0X80134 0X80135
0X8012B 0X8012C 0X8012D
0X80123 0X80124 0X80125
0X8011B 0X8011C 0X8011D
0X80113 0X80114 0X80115
0X8010B 0X8010C 0X8010D
0X80103 0X80104 0X80105
DY MODIFY
THE DY MODIFY FIELD CONTAINS THE OFFSET
ADDED TO THE LAST ADDRESS IN THE ROW TO
POINT TO THE N EXT ELEMENT IN THE Y
DIMENSION. IN THIS EXAMPLE AS THE OPERAND
LENGTH IS QUAD, THE LAST ADDRESS POINTED TO
IN THE ROW IS 0X80104. THE NEXT ELEMENT IN THE
Y DIMENSION IS THE FIRST ELEMENT IN THE NEXT
ROW, 0X80108. THUS THE OFFSET VALUE IS 0X4.
regis-
DCIX
register.
reg-
TCB DX Count
0X8013E 0X8013F
0X80136 0X80137
0X8012E 0X8012F
0X80126 0X80127
0X8011E 0X8011F
0X80116 0X80117
0X8010E 0X8010F
0X80106 0X80107
7-47