msm7730 Oki Semiconductor, msm7730 Datasheet - Page 11

• Manufacturer Part Number: msm7730
• Description: Wireless Lan Baseband Controller
• Manufacturer: Oki Semiconductor

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MSM7730
Preamble
Scrambler
Data Whitener
Formatting
MOD
PHY
State Machine
DEMOD
Header
De-whitener
De-scrambler
CRC Check
Add arrows
Figure 7. Physical Layer Convergence Protocol Block Diagram
Each frame starts with an 80-bit synchronization sequence or preamble, followed by a 16-bit unique
word or start of frame deliminiter (SFD).
The Physical Data Unit (PDU) is a data-whitened version of the MAC data at either 1 or 2 Mbps. The pre-
amble and header are always transmitted at 1 Mbps. The PDU can be transmitted at either 1 or 2 Mbps.
The PHY is required to perform CCA to determine when to transmit, and for the MAC to control the con-
tention back-off timer.
PCMCIA Interface
The MSM7730 provides a PCMCIA host interface mode designed to permit implementation of PC cards
for use with host computers compatible with the PCMCIA PC card standard (Revision 2.1). The interface
supports 16-bit transfers to maximize overall system throughput. In addition, common memory may be
used to access all control registers. This is useful for low-cost card implementations that do not have a
local processor.
The MSM7730 uses attribute memory to configure the device and card. The device decodes the least-sig-
nificant 9-bits of PC card address space, allowing for an attribute memory size of 512 bytes located at
addresses 0x000 - 0x1FF. The attribute memory stores the PCMCIA registers as well as the card informa-
tion structure (CIS) table data. The PCMCIA standard defines four configuration registers. However,
only the Configuration Option and the Configuration and Status registers are supported, not the Pin Replace-
ment and Socket and Copy registers.
The CIS information data is stored in an off-chip serial EEPROM. When the MSM7730 is reset, the con-
tents of the EEPROM are downloaded to shared RAM. Then the information is mapped to attribute
memory space.
Oki Semiconductor
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