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App Notes

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2.12 - DB15

DB15 Overview

The DB15 connector brings out 12 additional digital I/O.  It has the potential to be used as an expansion bus, where the 8 EIO are data lines and the 4 CIO are control lines.

Note that on the U6/U6-Pro the digital lines CIO0-2 and MIO0-2 are shared. This means that changing the state of MIO0-2 will also change the state of CIO0-2. Therefore, anyone using two accessory boards with a U6 needs to be aware that they can use either CIO0-2 or MIO0-2, but cannot use both simultaneously.  MIO0-2 are used to control extended analog channels, so if you are reading extended channels from the Mux80 you do not want to use slots 8-10 on the RB12 (only use slots 0-7 & 11).

In the Windows LabJackUD driver, the EIO are addressed as digital I/O bits 8 through 15, and the CIO are addressed as bits 16-19.

0-7    FIO0-FIO7
8-15   EIO0-EIO7
16-19  CIO0-CIO3

These 12 channels include an internal series resistor that provides overvoltage/short-circuit protection.  These series resistors also limit the ability of these lines to sink or source current.  Refer to the specifications in Appendix A.

All digital I/O on the U6 have 3 possible states: input, output-high, or output-low.  Each bit of I/O can be configured individually.  When configured as an input, a bit has a ~100 kΩ pull-up resistor to 3.3 volts.  When configured as output-high, a bit is connected to the internal 3.3 volt supply (through a series resistor).  When configured as output-low, a bit is connected to GND (through a series resistor).

 Table 2.12-1. DB15 Connector Pinouts

DB15 Pinouts       
1 Vs   9 CIO0
2 CIO1   10 CIO2
3 CIO3   11 GND
4 EIO0   12 EIO1
5 EIO2   13 EIO3
6 EIO4   14 EIO5
7 EIO6   15 EIO7
8 GND      

Figure 2.12-2. standard DB15 pin numbers looking into the female connector on the U6.