MAS3549F datasheet(27/92 Pages) MICRONAS

27 / 92 page

DATA SHEET

MAS 35x9F

Micronas

June 30, 2004; 6251-505-1DS

3.3. DSP Core

3.3.1. Access Protocol

The I2C data register is used to communicate with the

internal firmware of the MAS 35x9F. It is readable

(subaddress “data_read”) and writable (subaddress

“data_write”) and also has a length of 16 bits. The data

transfer is done with the most significant bit (m) first.

A special command language is used that allows the

controller to access the DSP registers and RAM cells

and thus monitor internal states, set the parameters for

the DSP firmware, control the hardware, and even pro-

vide a download of alternative software modules. The

DSP commands consist of a “Code” which is sent to

the I2C data register together with additional parame-

ters.

Fig. 3–2: General core access protocol

Table 3–5 gives an overview over the different com-

mands which the DSP Core receives via the I2C data

transmitted after the “data_write” subaddress byte. A

second auxiliary code nibble is used for the short

memory (16-bit) access commands.

The MAS 35x9F firmware scans the I2C interface peri-

odically and checks for pending or new commands.

The commands are then executed by the DSP during

its normal operation without any loss or interruption of

the incoming data or outgoing audio data stream.

However, due to some time critical firmware parts, a

certain latency time for the response has to be

expected at the locations marked with a “W” (= wait).

The theoretical worst case response time does not

exceed 4 ms. However, the typical response time is

less than 0.5 ms.

Due to the 16-bit width of the I2C data register, all

actions transmit telegrams with multiples of 16 data

bits.

Table 3–4: Data register bit assignment

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

...

SDW

data_write

Code,...

...,...

Table 3–5: Basic controller command codes

Code

(hex)

Command

Function

0...3

Run

Start execution of an internal program. Run with start address 0 means

freeze the operating system.

Read Ancillary Data

The controller reads a block of MPEG Ancillary Data from the MAS 35x9F

Fast Program Download

The controller downloads custom software via the PIO interface

Read IC Version

The controller reads the version information of the IC

Read from Register

The controller reads an internal register of the MAS 35x9F

Write to Register

The controller writes an internal register of the MAS 35x9F

Read D0 Memory

The controller reads a block of the DSP memory

Read D1 Memory

The controller reads a block of the DSP memory

Write D0 Memory

The controller writes a block of the DSP memory

Write D1 Memory

The controller writes a block of the DSP memory

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