CYW43353 datasheet(39/113 Pages) CYPRESS

39 / 113 page

Document No. 002-14949 Rev. *F

Page 39 of 113

PRELIMINARY

CYW43353

8. WLAN Global Functions

8.1 WLAN CPU and Memory Subsystem

The CYW43353 WLAN section includes an 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 is intended

for deeply embedded applications that require fast interrupt response features. Delivering more than 30% performance gain over

ARM7TDMI, the ARM Cortex-R4 implements the ARM v7-R architecture with support for the Thumb®-2 instruction set.

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.

Using multiple technologies to reduce cost, the ARM Cortex-R4 offers improved memory utilization, reduced pin overhead, and

reduced silicon area. It supports independent buses for Code and Data access (ICode/DCode and System buses), and extensive

debug features including real time trace of program execution.

On-chip memory for the CPU includes 768 KB SRAM and 640 KB ROM.

8.2 One-Time Programmable Memory

Various hardware configuration parameters may be stored in an internal One-Time Programmable (OTP) memory, which is read by

the system software after 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. Customer accessible OTP memory is 502 bytes.

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 Cypress 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 memory programming, all values should be verified using the appropriate editable nvram.txt file, which is provided with

the reference board design package.

8.3 GPIO Interface

The following number of general-purpose I/O (GPIO) pins are available on the WLAN section of the CYW43353 that can be used to

connect to various external devices:

■ WLBGA package – 9 GPIOs

Upon power up and reset, these pins become tristated. Subsequently, they can be programmed to be either input or output pins via

the GPIO control register. In addition, the GPIO pins can be assigned to various other functions (see Table 21, “CYW43353 GPIO/

SDIO Alternative Signal Functions,”).

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