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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Functional Overview
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
56
Reference Number: 306262-004US
At the de-assertion of reset, the address bus is used to capture configuration
information from the levels that are applied to the pins at this time. External pull-up/
pull-down resistors are used to tie the signals to particular logic levels. (For additional
details, refer to the Expansion Bus Controller section of this document).
2.1.9
High-Speed, Serial Interfaces
The high-speed, serial interfaces (HSS) are six-signal interfaces that support serial
transfer speeds from 512 KHz to 8.192 MHz, for some models of the IXP45X/IXP46X
network processors. (For processor-specific speeds, refer to the HSS chapter.)
Each interface allows direct connection of up to four T1/E1 framers and CODEC/SLICs
to the IXP45X/IXP46X network processors. The high-speed, serial interfaces are
capable of supporting various protocols, based on the implementation of the code
developed for the network processor engine.
For a list of supported protocols, see the Intel
®
IXP400 Software Programmer’s Guide.
2.1.10
UARTs
The UART interfaces are a 16550-compliant UART with the exception of transmit and
receive buffers. Transmit and receive buffers are 64 bytes-deep versus the 16 bytes
required by the 16550 UART specification.
The interfaces can be configured to support speeds from 1,200 Baud to 921 Kbaud. The
interfaces support configurations of:
• Five, six, seven, or eight data-bit transfers
• One or two stop bits
• Even, odd, or no parity
The request-to-send (RTS_N) and clear-to-send (CTS_N) modem control signals also
are available with the interface for hardware flow control.
2.1.11
GPIO
There are 16 GPIO pins supported by the IXP45X/IXP46X network processors. GPIO
pins 0 through 13 can be configured to be general-purpose input or general-purpose
output. Additionally, GPIO pins 0 through 12 can be configured to be an interrupt input.
GPIO Pin 14 can be configured similar to GPIO Pin 13 or as a clock output. The output-
clock configuration can be set at various speeds, up to 33 MHz, with various duty
cycles. GPIO Pin 14 is configured as an input, upon reset.
GPIO Pin 15 can be configured the same as GPIO Pin 13 or as a clock output. The
output-clock configuration can be set at various speeds, up to 33 MHz, with various
duty cycles. GPIO Pin 15 is configured as an output, upon reset. GPIO Pin 15 can be
used to clock the expansion interface, after reset.
Several other GPIO pins can serve as an alternate function. These functions are
outlined in
below.