AK7750 Datasheet, PDF(36/77 Page) Asahi Kasei Microsystems – Audio DSP with Built-in Hands-Free Phone Features

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AK7750 Datasheet, PDF (36/77 Pages) Asahi Kasei Microsystems – Audio DSP with Built-in Hands-Free Phone Features

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[ASAHI KASEI]

[AK7750]

2) CONT1: RAM control

This register should be changed only during a system reset ( S_RESET =âLâ).

Command Code Name

Write Read

62h

72h

CONT1 DATARAM

BANK1 BANK0 CMP_N

SS1

SS0

D0 Default

0000_000x

c D7:DATARAM DATARAM addressing mode selector

0: Ring addressing mode

1: Linear addressing mode

DATARAM is 256-words x 24-bits and has 2 addressing pointers (DP0, DP1).

Ring addressing mode: The starting address increments by 1 every sample period.

Linear addressing mode: The starting address is always the same, DP0 = 00h and DP1 = 80h.

d D6:RM: Decompress bit mode

0: SIGN bit

1: Random data

When either Data Compression or Data Expansion mode is selected (CMP-N (D3) = â0â), data for the

lower bits where no data exists at the data expansion is selectable. When it is â0â, the sign bit is filled

in and when it is â0â, the M-series random number is filled in.

e D5,D4:BANK[1:0] DLRAM Setting

Mode BANK1

BANK0

Memory

24bit 1kword(RAM A)

16bit 2kword(RAM A),24bit 1kword(RAM B)

24bit 1kword(RAM A),16bit 2kword(RAM B)

16bit 4kword(RAM A)

note) When a hands-free function is used, set the DLRAM at mode0, which allocates the memory for

hands-free processing.

At DLRAM mode3, both Pointers 0 & 1 can be used. With DLRAM modes0, 1 and 2, Pointer 0 is

allocated to RAM A and Pointer 1 is allocated to RAM B.

f D3:CMP_N 16bitDLRAM Compress & Decompress selector

When mode 1,2 or 3 is selected, this register can turn ON or OFF the compress/decompress function.

0 : Compression / Expansion ON

1 : Compression / Expansion OFF

When both compression and expansion are enabled (ON), the upper 23 bit data on DBUS is

compressed to 15 bit data and it is written into DLRAM.

In read mode, the 15 bit data is expanded and the resulting data is output on DBUS.

Lower bit setting during data expansion follows as is set by D6 : RM.

With this data compression, 23 bit equivalent Dynamic Range and 15 bit equivalent S/N + D are

obtained.

When both compression and expansion are disabled (OFF), the upper 16 bit data on DBUS is directly

written into or read out of DLRAM. During the read operation, the lower 16 bit returns to DBUS a value

of 0000h.

g D2,D1:SS[1:0] DLRAM setting of sampling timing (only for RAM A)

Mode

SS1

SS0 RAM A mode selected by BANK[1:0]

Update every sampling time

Update every 2 sampling time

Update every 4 sampling time

Update every 8 sampling time

Note) When modes 1,2 or 3 are selected, aliasing will occur.

h D0: set to â0â

Note) Underlines â_â mean default setting.

[MS0296-E-00]

2005/03

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