AK7744VT Datasheet, PDF (30/50 Pages) Asahi Kasei Microsystems – 24bit 3ch ADC + 24bit 4ch DAC with Audio DSP

[ASAHI KASEI]
[AK7744]
(7) Interface with microcomputer
The microcomputer interface uses 6 control pins; RQ (ReQuest Bar), SCLK (Serial data input Clock), SI (Serial
data Input), SO (Serial data Output), RDY (ReaDY) and DRDY (Data ReaDY).
In the AK7744, two types of operations are provided; writing and reading during the reset phase (namely, system
reset) and R/W during the run phase.
During the reset phase, writing of the control register, program RAM, coefficient RAM, offset RAM, external
conditional jump code, and reading of the program RAM, coefficient RAM and offset RAM, are enabled.
During the run phase, writing of coefficient RAM, offset RAM and external conditional jump code, and reading of
data on the DBUS (data bus) from the SO, are enabled. Its data is MSB first serial I/O.
When the AK7744 needs to transfer data to the microcomputer, it starts by RQ going “L” expects reading of data
on the DBUS. The AK7744 reads SI data at the rising point of SCLK, and outputs to SO at the falling point of SCLK.
The AK7744 accepts first data as command then address data or some kinds of data input / output starts.
When RQ changes to “H”, one command has finished. New command requests must set RQ to “L” again. For
DBUS data reads, leave RQ =”H”. (It does not need command code input.)
When it needs to clear the output buffer (MICR), the SI pin uses for control. (In this case, it is necessary to protect
against a noise as SCLK.)
Command code table is as follow.
Conditions
for use
RESET
phase
RUN
phase
Code name
CONT0
CONT1
CONT2
CONT3
PRAM
CRAM
OFRAM
External condition jump
CRC check (R(x))
CRAM rewrite preparation
CRAM rewrite
OFRAM rewrite preparation
OFRAM rewrite
External condition jump
CRC check (R(x))
Command code list
Command code Remark:
WRITE READ
60h
70h For the function of each bit,
64h
74h See the description of Control
68h
78h Registers.
6Ch
7Ch
C0h
C1h
A0h
A1h
90h
91h
C4h
-
B6h
D6h
A8h
-
It needs to do before CRAM rewrite
A4h
-
98h
-
It needs to do before OFRAM rewrite
94h
-
C4h
-
Same code as RESET
B6h
D6h Same code as RESET
NOTE: Do not send other than the above command codes. Otherwise an operation error may occur.
If there is no communication with the microcomputer, set the SCLK to "H” and the SI to "L" for use.
<MS0167-E-00>
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2002/10