SMART 6806800K30J, Инструкция по установке и использованию

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Functional Description
RTM-ATCA-F125 Installation and Use (6806800K30J) 37
The LEDs are controlled by a PCF8574-type I2C parallel I/O expander. The ports of this are
connected as shown in Table 4-2.
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.
4.2.4 I2C Address Map
Table 4-3 summarizes the I2C address assignments.
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
Table 4-3 I2C Bus Address Map
Address Device
0x40 I/OExpander (LED control)
0x90 Temperature sensor (top)