INSTALLING GATEWAYS ON THE DEVELOPER BOARD
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MultiConnect® OCG-E MT100EOCG-EV3 Developer Guide
> 2.3 V for a high
< 1V for a low
GPI pins are 5 V tolerant. GPI pins have a 10K pull-downs to ground. This increases the input current to 330 uA
from the standard 1uA.
GPO pins output range:
> 2.58 V@4ma is a high
<= .36 V @4ma is a low
Maximum current on a GPO pin is +25 mA not to exceed 70ma total for all 4 GPO.
GPIO11 / GPIO 12 and SPI/I2C pins:
These are directly connected to the processor.
If the pin is programmed as an output, the high is 2.9V minimum and low is 0.4V maximum with a maximum
current draw of 8 mA. If the pin is programmed as an input, a high must be greater than 2.3V and a low
must be less than 1V.
These pins also have an optional pull-up resistor with a range of 40k ohm to 190k ohm, with a typical value
of 75k ohm.
Otherwise the input leakage is 1 uA.
Additional hardware is needed to drive the I2E and SPI signals if any additional wire is added to the signals.
For the I2C there are bus repeaters available that would be suitable, for example, Texas Instruments
LEVEL-TRANSLATING I2C BUS REPEATER PCA9517.
For the SPI signal, any logic level buffer that works at 3.3V would work.
LED Signals
GPO1-GPO4,LED1, and LED4-LED6 are sourced from the same IC.
Each pin can source 25 mA, but all pins, 4 GPO and 4 LED, can only source 70 mA total. This means the
cumulative output current of those pins is limited by the maximum output current rating of the IC.
GPO1-4 each can drive +25 mA, but total for all four is 70 mA (25 mA * 4 = 100 mA, but it cannot drive
that much all at the same time). It also means that if the IC dies, then all of those outputs die.
LED2 is directly connected to the processor GPIO pin PA30 and has the same characteristics as GPIO11
and GPIO12. The default operation of LED2 in CoreCDP is as a Linux Status indicator.
LED3 is sourced by a LVC open drain buffer and has a max current draw of 32 mA. LED3 is directly
connected to the Link Status pin of the device and is therefore dedicated.
LED7 and LED8 are driven directly by the Ethernet PHY chip and can drive about 4 mA. They are usually
used for Ethernet speed, link, and activity indicators.
