AK7746 Datasheet, PDF (27/62 Pages) Asahi Kasei Microsystems – Audio DSP with 5-channel 24-bit ADC and Input Mux

[ASAHI KASEI]
[AK7746]
2-2) CONT1 : RAM control
Recommend changing this register during the system reset state ( S_RESET =”L”).
Command
Code
WR
62h 72h
Name
CONT1
D7
DRAM
D6
D5
D4
D3
RM
BANK[1] BANK[0] CMP_N
D2
SS[1]
D1
SS[0]
D0 Default
× 0000 000X
c D7:DATARAM DATARAM addressing mode selector
0: Ring addressing mode
1: Linear addressing mode
DATARAM has 256-word x 24-bit and has 2 addressing pointer (DP0, DP1).
The Ring addressing mode: starting address increments by 1 every sample period.
The Linear addressing mode: starting address is always the same, DP0 = 00h and DP1 = 80h.
d D6:RM: Decompress bit mode
0: SIGN bit
1: Random data
When Compress & Decompress modes (D3:CMP_N = 0) are selected, this bit determines the decompressed LSB bits.
e D5,D4:BANK[1:0] DLRAM Setting
Mode BANK1:D5 BANK0:D4
Memory
0
0
0
24-bit 3kword(RAM A)
1
0
1
12-bit 6kword(RAM A)
2
1
0
12-bit 4kword(RAM A),24bit 1kword(RAM B)
3
1
1
24-bit 1kword(RAM A),12bit 4kword(RAM B)
Note) When mode 0 or 1 is selected, pointer 0 and 1 are available for both RAM area.
When mode 2 or 3 is selected, pointer 0 is available for RAM A and pointer 1 is available for RAM B.
When DLRAM is not used, mode 2 or 3 should be selected.
f D3:CMP_N 12bitDLRAM Compress & Decompress selector
When mode 1, 2 or 3 is selected, this register can set the compress/decompress function.
0: Compress & Decompress function ON
When data is written to DLRAM the DBUS data is compressed to 12-bits. and when it data is read from DLRAM, it is
decompressed to 24-bits.
1: Compress & Decompress function OFF
It always writes to DLRAM MSB 12-bit of DBUS data and it read from MSB 12-bit of DLRAM and add to 000h for LSB bits.
g D2,D1:SS[1:0] DLRAM setting of sampling timing (only for RAM A)
Mode
SS[1]:D2 SS[0]:D1 RAM A mode selected by BANK[1:0]
0
0
0
Update every sampling time
1
0
1
Update every 2 sampling time
2
1
0
Update every 4 sampling time
3
1
1
Update every 8 sampling time
Note) When the mode 1,2 or 3 is selected, it comes out aliasing.
h D0: Input always 0
When inputs D0, CONT1 setting is fixed.
Note) Underlines of the setting of “_” mean default setting.
[MS0369-E00]
- 27 -
2004/12