DATA SHEET
MAS 35x9F
Micronas
June 30, 2004; 6251-505-1DS
29
3.3.2.4. Read Memory (Codes C
hex
and D
hex
)
The MAS 35x9F has 2 memory areas of 2048 words
denoted D0 and D1. The memory areas D0 and D1
can be written by using the codes C
hex
and D
hex
,
respectively.
The
Read D0 Memory
command gives the controller
access to all 20 bits of the D0/D1 memory cells. The
telegram to read 3 words starting at location D1:100 is
<DW 68 d0 00 00 03 01 00>
<DW 69 <DR
xx xd dd dd
xx xd dd dd
xx xd dd dd
>
3.3.2.5. Short Read Memory
(Codes C4
hex
and D4
hex
)
Because most cells in the user interface are only 16
bits wide, it is faster and more convenient to access
the memory locations with a special 16-bit mode for
reading:
This command is similar to the normal 20 bit read com-
mand and uses the same command code C
hex
and
D
hex
for D0 and D1 memory, respectively, however it is
followed by a 4
hex
rather than a 0
hex
.
Example: Read 16 bits of D1:123 has the following I
2
C
protocol:
<DW 68 d4 00
00 01
01 23
<DW 69 DR
dd dd
>
read 16 bits from D1
1 word to be read
start address
start reading
and read
3.3.2.6. Write Memory
(Codes E
hex
and F
hex
)
The memory areas D0 and D1 can be written by using
the codes E
hex
and F
hex
, respectively.
With the
Write D0/D1 Memory
command n 20-bit
memory cells in D0 can be initialized with new data.
Example: Write 80234
hex
to D1:456 has the following
I
2
C protocol:
<3a 68 f0 00
00 01
04 56
00 08
02 34>
write D1 memory
1 word to write
start address
value = 80234
hex
3.3.2.7. Short Write Memory
(Codes E4
hex
and F4
hex
)
For faster access only the lower 16 bits of each mem-
ory cell are written. The 4 MSBs of the cell are cleared.
The command uses the same codes E
hex
and F
hex
for
D0/D1 as for the 20-bit command but followed by a 4
rather than a 0.
3.3.2.8. Clear SYNC Signal
(Code 5
hex
)
After a successful decoding of an MPEG frame the sig-
nal at pin SYNC rises and thus generates an interrupt
event for the microcontroller. Issuing this command
lets the signal at pin SYNC return to ‘0’.
1) send command (Read D0)
2) get register value
S
DW
data_write
c
,0
0,0
S
DW
data_read
A
S
DR
A
P
n3,n2
n1,n0
P
a3,a2
a1,a0
A
A
A
N
A
A
....repeat for n data values....
W
A
A
A
W
A
A
W
A
A
W
A
W
A
A
W
A
d3,d2
W
W
d1,d0
x,d4
x,x
d3,d2
W
W
d1,d0
x,d4
x,x
1) send command (e.g. Short Read D0)
2) get register value
S
DW
data_write
W
c,4
0,0
S
DW
data_read
S
DR
P
n3,n2
n1,n0
P
a3,a2
a1,a0
A
A
N
A
....repeat for n data values....
W
A
A
A
A
A
W
A
A
W
A
W
A
W
A
A
d3,d2
W
d1,d0
d3,d2
W
d1,d0
S
DW
data_write
e
,0
0,0
x,x
x,d4
P
n3,n2
n1,n0
a3,a2
a1,a0
d3,d2
d1,d0
x,x
x,d4
d3,d2
d1,d0
....repeat for n data values....
W
A
A
A
W
A
A
W
A
A
W
A
A
W
A
A
W
A
A
W
A
A
W
A
S
DW
data_write
e,4
0,0
P
n3,n2
n1,n0
a3,a2
a1,a0
d3,d2
d1,d0
d3,d2
d1,d0
....repeat for n data values....
W
A
A
A
W
A
A
A
W
A
A
A
W
A
A
A
W
A
A
A
W
A
S
DW
data_write
5
,0
0,0
P
W
A
A
A
W
A