BCM4390DKWBGT Datasheet, PDF (29/78 Pages) Cypress Semiconductor – WICED™ Wi-Fi IEEE 802.11 b/g/n SoC with Embedded Application Processor

BCM4390 Advance Data Sheet
WLAN Global Functions
Section 6: WLAN Global Functions
WLAN CPU and Memory Subsystem
The BCM4390 WLAN section includes an independent integrated ARM Cortex-R4™ 32-bit processor with
internal RAM and ROM. The ARM Cortex-R4 is a low-power processor that features low gate count, low
interrupt latency, and low-cost debug capabilities. It runs all WLAN firmware and provides support for the
standards-compliant WLAN implementation running independent of the applications processor. The Cortex-R4
processor is not available to customers for general purpose applications processing.
At 0.19 μW/MHz, the Cortex-R4 is the most power efficient general-purpose microprocessor available,
outperforming 8- and 16-bit devices on MIPS/μW. It supports integrated sleep modes.
One-Time Programmable Memory
Various hardware configuration parameters may be stored in an internal 6 Kbit one-time programmable (OTP)
memory, which is read by WICED bootstrap system software after a device reset. In addition, customer-specific
parameters, including the system vendor ID and the MAC address can be stored, depending on the specific
board design.
The initial state of all bits in an unprogrammed OTP device is 0. After any bit is programmed to a 1, it cannot
be reprogrammed to 0. The entire OTP array can be programmed in a single write cycle using a utility provided
with the Broadcom WLAN manufacturing test tools. Alternatively, multiple write cycles can be used to
selectively program specific bytes, but only bits which are still in the 0 state can be altered during each
programming cycle.
Prior to OTP programming, all values should be verified using the appropriate editable nvram.txt file, which is
provided with the reference board design package.
UART Interface
One 2-wire UART interface can be enabled by software as an alternate function on GPIO pins. Provided
primarily for debugging during WLAN development, this UART enables the BCM4390 to operate as RS-232 data
termination equipment (DTE) for exchanging and managing data with other serial devices. It is compatible with
the industry standard 16550 UART, and provides a FIFO size of 64 × 8 in each direction.
BROADCOM ®
February 5, 2014 • 4390-DS103-R
WICED Wi-Fi IEEE 802.11 SoC w/Embedded App Processor
Page 28
BROADCOM CONFIDENTIAL