MAS3506D datasheet(13/52 Pages) MICRONAS

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PRELIMINARY DATA SHEET

MAS 3506D

Micronas

3. Controlling

3.1. I2C-Access

Communication between the MAS 3506D and the

external controller is done via an I2C slave interface.

3.1.1. Device Address

The device addresses are 3ahex for writing (DW) and

3bhex for reading (DR), respectively. I

2C clock syn-

chronization is used to slow down the bus if required.

3.1.2. I2C Registers and Subaddresses

The interface uses one level of subaddresses. The

MAS 3506D interface has 3 subaddresses allocated

for the corresponding I2C-registers.

The address 6ahex is used for basic control, i.e. reset

and task select. The other addresses are used for data

transfer from/to the MAS 3506D.

The I2C-control and data registers of the MAS 3506D

are 16 bits wide, the MSB is denoted as bit [15]. Trans-

missions via I2C-bus have to take place in 16-bit words

(two byte transfers, MSB sent first); thus for each reg-

ister access two 8-bit data words must be sent/

received via I2C-bus.

3.1.3. Conventions for the Command Description

The description of the various controller commands

uses the following formalism:

– Abbreviations used in the following descriptions:

address

data value

count value

offset value

don’t care

– Memory addresses like D1:89f are always in hexa-

decimal notation.

– A data value is split into 4-bit nibbles which are

numbered beginning with 0 for the least significant

nibble.

– Data values in nibbles are always shown in hexa-

decimal notation.

– A hexadecimal 20-bit number d is written, e.g. as

d = 17c63hex, its five nibbles are

d0 = 3hex, d1 = 6hex, d2 = chex, d3 = 7hex, and d4 =

1hex.

– Variables used in the following descriptions:

3ahex

I2C-device write

3bhex

I2C-device read

data_write

68hex

data register write

data_read

69hex

data register read

control

6ahex

control register write

– Bus signals

SStart

PStop

ACK = Acknowledge

NAK = Not acknowledge

W Wait = a wait time (

≤ 4 ms) may occur

– Symbols in the telegram examples

Start condition

Stop

data byte

ignore

All telegram digits are hexadecimal, data originating

from the MAS 3506D are grayed.

Example:

<3a 68 dd dd>

write data to DSP

<3a 69 <3b dd dd >

read data from DSP

Figure 3–1 shows I2C bus protocols for read and write

operations of the interface; the read operation requires

an extra start condition and repetition of the I2C-device

address with the read command (DR). Fields with sig-

nals/data originating from the MAS 3506D are marked

by a gray background. Note that in some cases the

data reading process must be concluded by a NAK

condition.

The MAS 3506D firmware scans the I2C interface peri-

odically and checks for pending or new commands.

Table 3–1: I2C device address bits

write/

read

001

11010/1

Table 3–2: I2C subaddresses

Sub-

address

I2C-

Function

68hex

data_write

Controller writes to

MAS 3506D data register

69hex

data_read

Controller reads from

MAS 3506D data register

6ahex

control

Controller writes to

MAS 3506D control register

MAS3506D Datasheet(PDF) 13 Page - Micronas

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