AK7712A-VT Datasheet, PDF (29/87 Pages) Asahi Kasei Microsystems – Built-in 20-bit ADC/DAC Sophisticated Audio DSP

ASAHI KASEI
[AK7712A-VT]
Together with shift function, each double-precision calculations of (24 × 31-bit), (45 × 31-bit) and (45 × 16-bit) are
available.
, (24 × 31-bit) Calculation
(24 × 31-bit) calculation is done with Coefficient RAM data regulated as follows.
The obtained value X × YH should be added after shifting 16 bits to left compared with X × YL. But, as X × YL is the
data which is shifted 1bit to right, actually X × YH is added after shifting 15 bits to left.
<Example of Calculation Program (24 × 31-bit)>
,OP,
,
,CPU,DU1,,, ;Read of Coefficient(MSB) and Data
,OP,
,
,OP,CR × DR ,
,CPU, ,,, ;Read of Coefficient(LSB)
, , ,,,
,OP,CR × DR ,
, , ,,,
,OP, ,IDR0=SH0 <<
, , ,,,
,OP, ,IDR0=SHRF + LDR0 , , ,,, ;(X × YH) + 15-bit right-shifted (X × YL)
0180-E-02
- 29 -
1997/12