DM562P
V.90 Integrated Data/ Fax/Voice/Speakerphone
Modem Device Single Chip with Memory Built in
DM6580 Functional Description
In this chip, we could roughly divide it into two major
parts: digital portion and analog portion. The
functional blocks are described separately in this
section. The analog circuits include a sigma-delta
modulator/demodulator, decimation/interpolation
filters, a speaker driver, low-pass filter and certain
logic circuits. The digital circuits is composed of
Tx/Rx clock generator/PLL, serial port, serial/parallel
conversions and control registers. All the clock
information the analog circuits need should be
provided by the digital clock system since the best
sampling instant of A/D and D/A depends on the
received signal and transmit signals. The data format
of A/D and D/A is 2's complement.
The master clock (FQ) is obtained from an external
signal connected to CLKIN. The different transmit
and receive clocks are obtained by master clock
frequency division in several programmable counters.
The Tx and Rx clocks can be synchronized on
external signals by performing the phase shifts in the
frequency division process. Two independent digital
phase locked loops are implemented using this
principle, one for transmit clock system, the other,
receive clock. The tracking of the transmit clock is
automatically done by the transmit DPLL circuit. The
receive DPLL circuit is controlled by the host
processor and it is actually an adjustable phase
shifter.
DM6580 Register Description
Register
TxCR0
TxCR1
TxCR2
D11
D10
D9
D8
X1
D
D7
X0
M1
F0
D6
N3
M0
W
D5
N2
D4
N1
F
D3
N0
Y
D2
R0
D1
S
D0
T
Programme
dFunctions
R1
X3
X2
Tx Data Rate
Clock
Q1
Q0
U2
U1
U0
VF
Tx Baud
sample Clock
Miscellaneou
s control
Reserved
Vol1
Q1
Vol2
F1
ATT
LTX
LC
SST
EMX
TxTest
RxCR0
R1
H2
H1
D
H0
M1
N3
M0
N2
Q0
N1
P
N0
Y
R0
U2
S
T
Rx Data Rate
Clock
Rx Baud
SampleClock
Rx Phase
RxCR1
RxCR2
RxTest
RST
-6dB
U1
U0
LL
PS4
PS3
PS2
PS1
PS0
AP2
AP1
AP0
Shift Control
Reserved
Final
43
Version: DM562P-DS-F01
February 02, 2004
DAVICOM [ DAVICOM SEMICONDUCTOR, INC. ]
