DATA SHEET
MAS 35x9F
3.3. DSP Core
S
DW
W
A
data_write
A
Code,...
A
...,...
A
...
3.3.1. Access Protocol
Fig. 3–2: General core access protocol
2
The I C 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.
Table 3–5 gives an overview over the different com-
mands which the DSP Core receives via the I C data
register. The “Code” is always the first data nibble
transmitted after the “data_write” subaddress byte. A
second auxiliary code nibble is used for the short
memory (16-bit) access commands.
2
Table 3–4: Data register bit assignment
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
2
The MAS 35x9F firmware scans the I C interface peri-
m
l
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.
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
2
the I C data register together with additional parame-
ters.
2
Due to the 16-bit width of the I C data register, all
actions transmit telegrams with multiples of 16 data
bits.
Table 3–5: Basic controller command codes
Code Command
(hex)
Function
0...3
Run
Start execution of an internal program. Run with start address 0 means
freeze the operating system.
5
6
7
a
b
c
d
e
f
Read Ancillary Data
Fast Program Download
Read IC Version
The controller reads a block of MPEG Ancillary Data from the MAS 35x9F
The controller downloads custom software via the PIO interface
The controller reads the version information of the IC
The controller reads an internal register of the MAS 35x9F
The controller writes an internal register of the MAS 35x9F
The controller reads a block of the DSP memory
Read from Register
Write to Register
Read D0 Memory
Read D1 Memory
Write D0 Memory
Write D1 Memory
The controller reads a block of the DSP memory
The controller writes a block of the DSP memory
The controller writes a block of the DSP memory
Micronas
June 30, 2004; 6251-505-1DS
27
MICRONAS [ MICRONAS ]
