MAS3506D datasheet(16/52 Pages) MICRONAS

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MAS 3506D

PRELIMINARY DATA SHEET

Micronas

3.3.1. Data Formats

The internal data word size is 20 bits. All RAM-

addresses can be accessed in a 20-bit mode via I2C-

bus. Because of the 16-bit width of the I2C-data regis-

ter the full transfer of all 20 bits requires two 16-bit I2C-

words. Some commands only access the lower 16 bits

of a cell. For fast access of internal DSP-states the

processor core also has an address space of 256 data

registers.

The internal data format is a 20 bit two’s complement

denoted “r”. If in some cases a fixed point notation “v”

is necessary. The conversion between the two forms

of notation is done as follows:

r = v*524288.0+0.5; (

−1.0 ≤ v < 1.0)

v = r/524288.0; (

−524288 < r < 524287)

3.3.2. Run and Freeze (Codes 0hex to 1hex)

The Run command causes the start of a program part

at address a = (a3,a2,a1,a0). Note that nibble a3 is

also the command code (see Table 3–5) and thus it is

restricted to certain values. This command is espe-

cially used to start alternate code or downloaded code

from a RAM-area that has been configured as program

RAM.

Example 1: Start program execution at address

345hex:

<3a 68 03 45>

Freeze is a special run command with start address 0.

It suspends all normal program execution. The operat-

ing system will enter an idle loop so that all registers

and memory cells can be watched. This state is useful

for operations like downloading code or contents of

memory cells because the internal program cannot

overwrite these values. This freezing will be required if

alternative software is downloaded into the internal

RAM of the MAS 3506D.

Freeze has the following I2C protocol:

<3a 68 00 00>

The entry point of the default software will be accessed

automatically after a reset, thus issuing a Run or

Freeze command is only necessary for starting down-

loaded software or special program modules which are

not part of the standard set.

3.3.3. Select Service Component (Code 5hex)

Select the (zero-based) service component with the

number d = d0. The number of available service com-

ponents is to be taken from the SCH information. A

maximum of 8 service components are allowed in one

Broadcast Channel. SC-selection is also possible by

writing to memory cell D1:7ef (see Table 3–11 on

page 23).

3.3.4. Read Ancillary MPEG Data (Code 6hex)

The availability of new ancillary data is indicated by the

MPEG-FRAME-SYNC signal in register c8hex or at the

corresponding pin. Ancillary data are available every

24 to 32 ms depending on the sample rate of the

MPEG-bitstream. The

instruction parameters are

embedded in the 3 nibbles o2..o0. The 6 MSBs indi-

cate the address offset counted in 16-bit words where

the read-out of the ancillary data shall start. The 6

LSBs indicate the number of 16-bit words that are to

be transmitted by MAS 3506D.

SDW

data_write

AAA

a3,a2

a1,a0

Table 3–6: Arrangement of o-bits

address offset

number of 16-bit words

SDW

data_write

5,0

0,0

0,d0

1) send command (Read D0)

2) get ancillary data values

SDW

data_write

6,o2

o1,o0

SDW

data_read

d3,d2

d1,d0

d3,d2

d1,d0

....repeat for n data values....

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