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2.13 - Hardware Revision Notes [U3 Datasheet]

The U3 has undergone three hardware revisions. 

U3A = Hardware Version 1.20

U3B = Hardware Version 1.21

U3C = Hardware Version 1.30

How to Determine Hardware Version:

  • Displayed by LJControlPanel.
  • Returned through the UD library using IOType LJ_ioGET_CONFIG with special channel LJ_chHARDWARE_VERSION.
  • Returned by the Low-level ConfigU3 function.
  • Printed on the serial number label on the bottom of the red enclosure.

Changes from 1.20 to 1.21:

Starting September of 2006, all U3 shipments changed from hardware revision 1.20 to 1.21.  Following are the some of the main changes in revision 1.21:

  • The default timer clock frequency is 48 MHz.
  • All TimerBaseClock frequencies are twice the previous frequencies.
  • The input timer edge limit is now 30,000 edges/second, compared to the old limit of 10,000 edges/second.
  • Stream mode is now supported.  See Section 3.2.
  • Other new functions are supported, including Watchdog, SPI, Asynch, I2C, and SHT1X.
  • Typical supply current is 50 mA.

Changes from 1.21 to 1.30:

Hardware revision 1.30 was released in mid-March 2008 with 2 variations:  U3-LV and U3-HV.  The U3-LV is the most compatible with the previous U3, and the only changes possibly affecting backwards compatibility are:

  • Timers/Counters cannot appear on FIO0-3.  TimerCounterPinOffset must be 4-8.  A value of 0-3 will result in an error.  This error can be suppressed by a power-up default setting in LJControlPanel.  If suppressed, a 0-3 will result in an offset of 4.
  • The 3.66 reference voltage is no longer available on the REF/DAC1 terminal.
  • There is no longer a buzzer.
  • SDA terminal is gone.  SCL terminal changed to SPC.
  • UART (Asynch functionality) no longer uses SDA and SPC terminals, but rather uses terminals dynamically assigned after timers and counters. Also, the BaudFactor is different.

Other changes:

  • Analog outputs are now specified for 10-bit resolution and DAC1 is always enabled.  The higher resolution is available with a new IOType in the low-level Feedback function, which the high-level UD driver uses automatically.  This causes the DACs to have more noise when the timer clock is decreased from the default of 48 MHz, so there is a compatibility option available in LJControlPanel to use 8-bit DACs.
  • On the U3-HV only, the first four flexible I/O are fixed as analog inputs (AIN0-AIN3), and have scaling such that the input range is ±10 volts normally, and +20 to -10 volts when using the “Special” range.  The input impedance of these four lines is roughly 1 MΩ, which is good, but less than the normal low voltage analog inputs.  Analog/digital configuration and all other digital operations on these pins are ignored.  FIO4-EIO7 are still available as flexible I/O, same as the U3-LV.
  • Timer and counter settings can be saved to startup defaults. 

Revision 1.20/21 U3s cannot be upgraded to 1.30.

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