STA321 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

STA321

4-channel digital audio system with FFX™ driver

STMicroelectronics 

Digital processing stage

STA321

6.14

6.14.1

Memory programming

Table 22 on page 47 shows the RAM mapping for the programmable functions in the signal

processing stage. Changing or reading this data is done through the I2C interface in either

single-word mode or in multi-word mode. Register PROCCTRL on page 107 sets the

desired mode and whether to read or write:

z 1-word mode:

this is for write only; the address of the memory location must be specified in registers

START_ADDR2 and START_ADDR1 on page 108 and the value of the parameter must

be written into registers I2CB0_TOP, I2CB0_MID and I2CB0_BOT on page 102.

z 5-word mode:

in this case it is possible to write/read 5 contiguous locations. Only the address of the

first one must be specified in registers START_ADD1-2, all the others are generated

automatically. The values of the parameters must be placed in (or taken from) registers

I2CB0_TOP-BOT, I2CB1_TOP-BOT, I2CB2_TOP-BOT, I2CA1_TOP-BOT,

I2CA2_TOP-BOT.

The 5-word mode is particular useful during the biquad programming when a set of five

coefficients needs to be updated. Not only is it more efficient to change all of them at the

same time but it avoids the generation of possible unpleasant acoustical side-effects.

The following sections explain how to implement this programming using the I2C interface.

Writing one coefficient/location to RAM

z Write RAM address to registers START_ADDR2 and START_ADDR1

z (b0) Write 8 MSBs of coefficient in register I2CB0_TOP

z Write 8 middle bits of coefficient in register I2CB0_MID

z Write 8 LSBs of coefficient in register I2CB0_BOT

z Write 1 to bit W1 in register PROCCTRL.

Figure 26. Writing RAM location

Write address to

START_ADDR[8:0]

0x61 = address[8]

0x62 = address[7:0]

Write top 8 bits

of coefficient

0x51 = top_val

Write middle 8 bits

of coefficient

0x52 = mid_val

Write bottom 8 bits

of coefficient

0x53 = bot_val

Write 1 to bit W1

in PROC_CTRL

0x60 = 0x01

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Doc ID 15351 Rev 3

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