Panasonic KX-TVM200E, Service Manual

Page: 129 / 164

DDR (DDR0, DDR1), DVRH, DVRL, DDX0, DDX1
Related register name:
P_RST, PBXMD, PBXIF, D_RST, DPTMD, DPTIF
With a 512Kbps ping-pong transmission (AMI encoding) interface, a transmission band of 2B (64kbps x 2) + D (16Kbps) +C
(8Kbps) is ensured. It also has the following functions: clock extraction through digital PLL, synchronization switching, DPT
interface, transmitted pulse width programmability, and receiving edge position programmability.
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Transmission frame format
The frame format on the transmission path is as shown in Fig.3-4: Frame timing; and transmissions are performed for each bit
shown in Table 3-1: Information field explanation table. Receiving operation from the PBX is performed, and after 1 bit time has
elapsed transmission operation is performed. After the parity bit is transmitted, an idle time of 7 bit times is commenced.
One bit time is 512KHz (1.95µs), and the information encoding used is AMI.
Table 3-1: Information Field Explanation
Field name Bit number Explanation
SYNC 5 Continuous [00000] pattern; used for clock extraction by PLL.
MAM 3 A [000] pattern (01-01-10) violating the AMI encoding side; used to detect the header of the
received frame.
C 1 Valid data inverted from B1 channel.
2
D 2 Valid data inverted from B2 channel
B1 8 Parity data, transmitted to PDX0/DDX0 line and PDX1/DDX1 line.Parity is added so that the
number of 0 patterns becomes equal.Combined with bit ensuring direct current balance on the
line.
B2 8 Continuous [00000] pattern; used for clock extraction by PLL.
P 1 A [000] pattern (01-01-10) violating the AMI encoding side; used to detect the header of the
received frame.
Table 3-2: AMI Encoding Rules
Voltage Level
PDR
Normal (PACT=0) Inversion (PACT=1) Information Bit
PDR0 PDR1 PDR0 PDR1
+1.75V 1 1 0 0 1
0V 1 0 0 1 0
+3.3V 0 1 1 0 0
- 0 0 1 1 Prohibited
PDX0,PDX1,DDR0,DDR1,DDX0 and DDX1 performs similar controls.
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KX-TVM200E / KX-TVM200NE