I 2 C Address Map; Table 4-2 Pcf 8574 Port Usage; Table 4-3 C Bus Address Map - SMART Embedded Computing RTM-ATCA-F140 Series Installation & Use Manual

The LEDs are controlled by a PCF8574-type I
connected as shown below.
Table 4-2
Port
0
1
2
3
4
5
6
7
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. 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 remain off until explicitly turned on by the IPMC.
For the blue LED an external FET inverter is used to ensure the LED is on at power-up. A
charge pump is used to provide adequate forward voltage if the LED cannot be operated
directly from 3.3V.
The I/O expander resides at I
2
4.2.4 I C Address Map
The next table summarizes the I
Table 4-3
Address
0x40
0x90
0x92
0x94
0xA0
RTM-ATCA-F140 Series Installation and Use (6806800M97M)
PCF 8574 Port Usage
Direction
Output
Output
Output
Output
Output
Output
N/A
Input
2
C address 0x40.
2
C address assignments.
2
I C Bus Address Map
Functional Description
2
C parallel I/O expander. The ports of this are
Connection
H/S LED (Blue)
OOS LED (Red)
IS LED (Green)
ATTN LED (Amber)
OOS LED (Amber)
FPGA PROM select
(not connected)
FPGA DONE
Device
I/O Expander (LED control)
Temperature sensor (top)
Temperature sensor (middle)
Temperature sensor (bottom)
Serial EEPROM
55