Atheros AR9271


 * The AR9271 is a USB to Wi-Fi single chip, typically used in Wi-Fi dongles.
 * For a list of all currently documented Atheros chipsets with specifications,
 * see Atheros.


 * Known chip revisions:
 * AR9271-AL1A
 * AR9271L-AL3A 'The first L stands for "Low-Cost".', per Sujith on ath9k-devel

Properties

 * Manufacturer: Atheros
 * Part name: AR9271
 * Type: chip
 * Number of buses: 1
 * Bus(es): USB 2.0. Probably Faraday FOTG210_UDC
 * Number of bands: 1
 * Band(s): 2.4GHz
 * Data rate: 150 Mbps
 * MIMO configuration:
 * 1x1 (1 txchain; 2 RX RF chains; 1 rx stream); see note below

.
 * IEEE 802.11 PHY Modes: b,g,n
 * First seen (FCC): 2009-07-27
 * Wireless adapters using this device:
 * Embedded systems using this device:
 * SOC Architecture: RISC - Tensilica core (Xtensa LX2.1.0) - see open firmware below.
 * SOC clock: 117 MHz
 * SOC ROM: 24 Kbyte
 * SOC RAM: 160 KByte


 * Output power:
 * (1Mbps): +19 dBm
 * (HT20 MCS7): +17 dBm
 * (HT40 MCS7): +16 dBm


 * Sensitivity (RX-only chain):
 * (1Mbps): -96 dBm typ.
 * (HT20 MCS7): -73 dBm typ.
 * (HT40 MCS7): -70 dBm typ.


 * Sensitivity for RX/TX shared chain:
 * 3dB worse than RX-only chain


 * Integrated RF: PA, LNA, T/R Switch
 * Integrated Functions: 802.11 Baseband, 802.11 MAC
 * Externally required functions: 2.4G antenna(s),
 * 40MHz crystal, SPI flash, serial EEPROM


 * Operating temperature range: 0C° to 110C°, typ 45C°


 * Marking on chip: Atheros (R); AR9271-AL1A; DOR379C; 1034; KOREA
 * Chip Package: 68 pin, 8mm x 8mm, LPCC package

Note about antenna diversity and MIMO: the chip has 2 RX RF chains with 4 analog (RF) combining methods, selected dynamically in real-time for each packet during reception, resulting in performance much closer to MIMO 1x2:1 than MIMO 1x1:1 even though it's not full MIMO-MRC... assuming a second antenna is connected to the secondary RX port, of course. Most adapters omit this second antenna.

Product Brief and Datasheet

 * Atheros AR9271 Product Brief PDF
 * Atheros AR9271 Datasheet PDF

Device ID
Default USB ID: Non-standard USB IDs:
 * 0cf3:9271 (Atheros AR9271)
 * Many, see query.

Linux support
Built-in Linux kernel support:
 * Linux kernel module: ath9k_htc
 *  in backports 
 * Linux kernel version: v2.6.35
 * Linux kernel date: 2010-08-01
 * Firmware: Open Firmware
 * In Ubuntu, the firmware files are already included in the base distribution
 * In Debian:
 * apt-get install firmware-atheros
 * (in Debian the firmware-atheros package includes files:
 * /lib/firmware/ar9271.fw /lib/firmware/htc_9271.fw
 * Without these modprobe ath9k_htc does not create wlan0 device and dmesg shows:
 * => Failed to load firmware )

Pins





 * 18 - GPIO5/SPI_SDO
 * 19 - GPIO6/SPI_S_L - chip select?
 * 20 - GPIO7/SPI_SCK
 * 21 - GPIO8/SPI_SDI
 * 28 - GPIO0/JTAG TMS - test mode select
 * 29 - GPIO1/JTAG TDI - test data input
 * 30 - GPIO2/JTAG TCK - test clock
 * 31 - GPIO4/JTAG TDO - test data output
 * 35 - GPIO12/SPI_BOOT - if UP on power on, CPU will start from SPI
 * 48 - GPIO9 and UART Rx
 * 49 - GPIO10 and UART Tx (baudrate 19200)
 * 67 - XPABIAS - (Analog Output) connected with EN(able) pin of external Power Amp.
 * 68 - PDET - (Analog Input) connected with DET ping of external Power Amp.

JTAG

 * "Before using those pins configure register “GPIO Input Enable and Value”
 * (H_GP_INPT_EN_VAL) Address: 0x1000_4054.
 * Bit 17 must be set to 0 that means JTAG enabled (1 means JTAG disabled)."