BCM4319 Preliminary Data Sheet
Global Functions
Section 4: Global Functions
General-Purpose Input/Output Interface
There are eight General-Purpose I/O (GPIO) pins on the BCM4319, which can be used to control various
external devices. Upon power-up and reset, these pins become tri-stated. Subsequently, they can be
programmed to be either input or output pins via the GPIO control register. If a GPIO output enable is not
asserted and the corresponding GPIO signal is not being driven externally, then the GPIO is read as high.
Each GPIO has a programmable option to enable/disable internal pull-up or pull-down (60 KΩ) resistors. The
default setting depends on the strapping options: if a strapping option is assigned to a GPIO pin then the default
pull is according to the default strapping value. Otherwise, there is no default pull on the GPIO.
GPIOs that do not have interfering strapping options can be safely used as input pins. All GPIOs can be safely
used in output mode.
Internal pull-up and pull-down resistors are active only when VDDC and VDDIO are present.
After the driver is loaded, the software disables the pull to reduce leakage.
UART Interface
One UART interface is provided, which enables the BCM4319 to operate as RS-232 data termination equipment
(DTE) for exchanging and managing data with other serial devices. The UART interface is primarily used for
debugging during development. It is compatible with the industry standard 16550 UART, and it provides a FIFO
size of 64 × 8 in each direction.
One-Time-Programmable (OTP) Memory
Various hardware configuration parameters may be stored in an internal 2k-bit OTP memory, which is read by
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. A programming utility is provided
with the Broadcom manufacturing test tools.
As an alternative to using the internal OTP, an external 4-wire SPROM interface can be enabled.
Broadcom®
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
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April 2, 2014 • 4319-DS05-R
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