uda1325 NXP Semiconductors, uda1325 Datasheet - Page 28

• Manufacturer Part Number: uda1325
• Description: Universal Serial Bus Usb Codec
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 23 ASR control register
START-UP BEHAVIOUR AND POWER MANAGEMENT
Start-up of the UDA1325
After power-on (of V
created by using the internal resistor (2
with the capacitor connected externally to the V
V
During 20 ms after Power-on reset becomes HIGH the UDA1325 has to initiate the internal registers. During this
initialisation, the user should prevent indicating the ‘connected’ status to the USB-host. This can be done by forcing the
DP-line LOW (i.e. via one of the GP pins).
Power Management
The total current drawn from the USB supply (for i.e. bus-powered operation of the UDA1325 application) must be less
than 500 A in suspend mode. In order to reach that low current target, the total power dissipation of the UDA1325 can
be reduced by disabling all internal clocks and switching off all internal analog modules.
Important note: In order to make use of power reduction (Power-down mode) and be able to restart after power-down, a
number of precautions must be taken!
1999 May 10
ADDRESS
DDA1
Universal Serial Bus (USB) CODEC
2000h
and V
SSA1
ASR control register
. The RC time can be calculated using R = 25000
DDA1
REGISTER
), an internal Power-on reset signal becomes HIGH after a certain RC time. This RC time is
robust word clock
serial I
digital I/O interface
phase inversion (on right mono
output)
bits per sample modi
mono or stereo operation
ASR register start-up mode
50 k ) divider for creating the reference voltage for the FSDAC in combination
2
REFDA
S-bus output format
COMMENTS
pin. The FSDAC and the internal resistor divider are supplied by
28
and C = C
6 and 5
3 and 2
BIT
7
4
1
0
ref
.
0 = off (not recommended)
1 = on (recommended)
00 = I
01 = 16-bit LSB justified
10 = 18-bit LSB justified
11 = 20-bit LSB justified
0 = mono phase inversal off
1 = mono phase inversal on
00 = reserved
01 = 8-bit audio
10 = 16-bit audio
11 = 24-bit audio
0 = mono
1 = stereo
0 = stop (e.g. at alternate
setting with bandwidth equal to
zero)
1 = go
2
S-bus
Preliminary specification
VALUE
UDA1325