11. Signals > Signal Groupings
222
Tsi578 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
Serial Port Speed Select
SP_IO_SPEED[1]
I/O,
LVTTL,
PU
Serial Port Transmit and Receive operating
frequency select, bit 1. When combined with
SP_IO_SPEED[0], this pin selects the default
serial port frequency for all ports.
00 = 1.25 Gbps
01 = 2.5 Gbps
10 =3.125 Gbps (default)
11 = Illegal
Selects the speed at which the ports operates
when reset is removed. This could be at either
HARD_RST_b being de-asserted or by the
completion of a self-reset.
These signals must remain stable for 10 P_CLK
cycles after HARD_RST_b is de-asserted in order
to be sampled correctly.
These signals are ignored after reset and software
is able to over-ride the port frequency setting in the
“SRIO MAC x Digital Loopback and Clock
Selection Register” on page 377
.
The SP_IO_SPEED[1:0] setting is equal to the
IO_SPEED field in the SRIO MAC x Clock
Selection Register.
Output capability of this pin is only used in test
mode.
Pin must be tied off according to
the required configuration. Either
a 10K pull-up to VDD_IO or a
10K pull-down to VSS_IO.
Internal pull-down may be used
for logic 0.
SP_IO_SPEED[0]
I/O,
LVTTL,
PD
See SP_IO_SPEED[1]
Pin must be tied off according to
the required configuration. Either
a 10K pull-up to VDD_IO or a
10K pull-down to VSS_IO.
Internal pull-up may be used for
logic 1.
Table 31: Tsi578 Signal Descriptions (Continued)
Pin Name
Type
Description
Recommended Termination
a