Emerson RTM-ATCA-F125, Installation And Use Instruction

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Functional Description
RTM-ATCA-F125 Installation and Use (6806800K30C)
37
z
Blue - Hot swap (initializing / shutting down)
z
Amber - Attention
The LEDs are controlled by a PCF8574-type I2C parallel I/O expander. The ports of this are
connected as shown in Table 2.
The I/O expander interrupt line is not connected.
For the red, green and amber LEDs the cathodes are connected directly to the I/O expander
pins and the anodes are connected to the management 3.3V supply through current limiting
resistors selected to limit the LED current to 15mA. Since the I/Os power-up in the high state,
this ensures that the LEDs will remain off until explicitly turned on by the IPMC. The control for
these LEDs is active low.
For the blue LED an external inverter is used to ensure the LED is lit at power-up and a charge
pump is used to provide adequate forward voltage in the case the LED cannot be operated
directly from 3.3V. The control for the blue LED is active high.
The PROM_SEL signal indicates which bank of FPGA FLASH is currently selected. The
FPGA_DONE signal indicates the FPGA load from FLASH is incomplete.
The I/O expander resides at I2C address 0x40.
Table 4-2 PCF 8574 Port Usage
Port Direction Connection
0 Output Blue LED
1 Output Red LED
2 Output Green LED
3 Output Amber LED
4 Output Amber LED (Alternate OOS)
5 Input PROM_SEL
6 Output (not connected)
7 Input FPGA_DONE