PRELIMINARY
CYW43438
5. Wireless LAN MAC and PHY
5.1 MAC Features
The CYW43438 WLAN MAC supports features specified in the IEEE 802.11 base standard, and amended by IEEE 802.11n. The
salient features are listed below:
■ Transmission and reception of aggregated MPDUs (A-MPDU).
■ Support for power management schemes, including WMM power-save, power-save multipoll (PSMP) and multiphase PSMP
operation.
■ Support for immediate ACK and Block-ACK policies.
■ Interframe space timing support, including RIFS.
■ Support for RTS/CTS and CTS-to-self frame sequences for protecting frame exchanges.
■ Back-off counters in hardware for supporting multiple priorities as specified in the WMM specification.
■ Timing synchronization function (TSF), network allocation vector (NAV) maintenance, and target beacon transmission time (TBTT)
generation in hardware.
■ Hardware off-load for AES-CCMP, legacy WPA TKIP, legacy WEP ciphers, WAPI, and support for key management.
■ Support for coexistence with Bluetooth and other external radios.
■ Programmable independent basic service set (IBSS) or infrastructure basic service set functionality
■ Statistics counters for MIB support.
5.1.1 MAC Description
The CYW43438 WLAN MAC is designed to support high throughput operation with low-power consumption. It does so without
compromising on Bluetooth coexistence policies, thereby enabling optimal performance over both networks. In addition, several
power-saving modes that have been implemented allow the MAC to consume very little power while maintaining network-wide timing
synchronization. The architecture diagram of the MAC is shown in Figure 16.
Figure 16. WLAN MAC Architecture
Embedded CPU Interface
Host Registers, DMA Engines
TX‐FIFO
32 KB
RX‐FIFO
10 KB
PSM
PMQ
PSM
UCODE
Memory
IFS
Backoff, BTCX
WEP
WEP, TKIP, AES
TSF
SHM
BUS
IHR
NAV
BUS
Shared Memory
6 KB
RXE
RX A‐MPDU
TXE
TX A‐MPDU
EXT‐ IHR
MAC
‐
PHY Interface
Document Number: 002-14796 Rev. *K
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