Artesyn COMX-P40x0 ENP2 Installation and Use (January 2015) - Manual (Page 88)

Functional Description
COMX-P40x0 ENP2 Installation and Use (6806800R95C) 88
4.18.3 I2C Device WDT
The watchdog timer M41T65Q is located on I2C1, U2101 and the device address is 0xD0. It is
able to generate a power-on reset and interrupt to the CPU.
4.18.4 I2C Device RTC
The real time clock M41T62LC6F is located on I2C2, U2100 and the device address is 0xD0. It
provides a 32 KHz clock output and interrupt to the CPU.
4.18.5 I2C Device Clock Generators
One clock generator ICS9FG104 is located on I2C1, U17 and the device address is 0xDC. The
second clock generator ICS9FG104 is located on I2C2, U40 with a device address of 0xDC.
The ICS9FG104 is a Frequency Timing Generator that provides four differential output pairs
that are compliant to the Intel CK410 specification. The part synthesizes several output
frequencies from 25 MHz crystal. It provides outputs with cycle-to-cycle jitter of less than 50
ps and output-to-output skew of less than 35 ps.
Frequency selection can be accomplished via strap pins or SMBus control. By default, strap pins
are used.
The input clock for the first clock generator is 25 MHz and three differential output pairs are
provided. First pair are connected to SerDes Bank 1, second pair are connected to two Aurora
connectors, and third pair are connected to COM Express connector. The second clock
generator also uses a 25 MHz input reference with three output pairs. The first pair drives
SerDes bank 2, the second pair drives SerDes bank 3, and the third is connected to the COM
Express connector.
The frequency of the first clock generator (bank 1 SerDes and Aurora) is selected through the
FS0 strap pin which is connected to GPIO23 of the CPU and pin B97 of the COM Express
connector. The frequency of the second clock generator (bank 2 and 3 SerDes) is also selected
through the FS0 strap pin which is connected to GPIO24 of the CPU and pin B98 of the COM
Express connector. For first and second clock generators, when FS0 is 0 (low level) the
frequency is 100 MHz and when FS0 is 1(high level) the frequency is 125 MHz.