Echelon Product Alerts
Defects in a Texas Instruments (TI) UART are affecting the operation of certain Echelon serial network interface products |
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Customer Notification
Date: October 14, 1998
Products Affected
SLTA/2, Model 73000 LTS-10, Model 65200 PSG/2, Model 73000-3 PSG-10,
Model 65200-200
Date Codes
9801 (January 1998)
to 9841 (October 1998)
Summary
This notice is to advise you that recently discovered defects in a
Texas Instruments (TI) UART are affecting the operation of certain Echelon
serial network interface products. The problems were discovered by customers
using the SLTA/2 Serial LonTalk� Adapters, however, this same UART is
also used in PSG/2, LTS-10, and PSG-10 products. TI has subsequently sent
notices to its UART customers advising them about the defect, and the
symptoms described in their notice match those experienced by our customers.
Affected Products
SLTA/2 units with date codes 9801x to 9841x (date code indicates year
(98), week (01), and revision (x) at the time of manufacture), and operating
at 5MHz clock speed and a serial port speed of 38400 bps or higher. Note
that Echelon does not recommend normal serial port operation at 115200
bps because of a known limitation with larger downlink packets.
SLTA/2 and LTS-10 units with date codes 9801x to 9841x, and operating at 10MHz clock speed and a serial port speed of 57600 bps or higher. Again, Echelon does not recommend normal serial port operation at 115200 bps because of a known limitation with larger downlink packets.
Note that PSG/2 and PSG-10 units use code written by the customer, not by Echelon. Depending on how this code affects the receiver FIFO stack, the PSG/2 and PSG-10 with date codes 9801x to 9841x may or may not experience serial communication errors.
Products Not Affected By This Notice
SLTA/2 and PSG/2 units with date codes 9801x to 9841x, and operating
at 5MHz clock speed and a serial port speed of 19200 bps or lower.
SLTA/2, PSG/2, LTS-10, and PSG-10 units with date codes 9801x to 9841x, and operating at 10MHz clock speed and a serial port speed of 38400 bps or lower.
SLTA/2, PSG/2, LTS-10, and PSG-10 units with date codes before or after 9801x to 9841x, and operating at any clock speed and any serial port speed.
The SLTA-10 Serial LonTalk� Adapters do not use the TI UART and are therefore not affected by this notice.
Description of the Problem
Due to a defect in the FIFO memory buffering of the TI UART, the UART
can lock-up under conditions of high serial traffic when operating with
a serial port speed of 38400 bps or higher and Neuron Chip clock speed
of 5 MHz, or a serial port speed of 57600 or higher and Neuron Chip clock
speed of 10 MHz. The problem can be cleared by resetting or repowering
the device.
Tests conducted by Echelon confirm that UARTs manufactured by other qualified suppliers work properly in the SLTA/2, PSG/2, LTS-10, and PSG-10 units at all specified serial port speeds.
What Should You Do?
If you are using SLTA/2, PSG/2, LTS-10, and/or PSG-10 units with date
codes 9801x to 9841x, inspect the units for the presence of the TI UART.
The TI UART is marked with the outline of the State of Texas and the letters
"TI" positioned vertically in the middle of the IC. The location of the
UART is as follows:
SLTA/2 and PSG/2: circuit board designation for the UART is U6 (located adjacent to the control module)
LTS-10 and PSG-10: circuit board designation for the UART is U7
If a unit has a TI UART and is identified above as being used in an
application that could encounter a receiver FIFO error, contact your local
Echelon Support Center to obtain a Return Material Authorization (RMA)
number. Do not under any circumstances return the units to Echelon without
an RMA number. Units that are returned will be reworked to replace the
defective TI UART, and then returned to the customer. If you have a critical
situation and cannot wait for rework, please discuss this with your Support
Center. Subject to availability of appropriate units, Echelon will arrange
for advance replacement of your units. Following is the contact information
for Echelon's Support Centers:
San Jose, California, USA
Tel: +1 408 938 5978
Fax: +1 408 328 3801
E-mail: lonsupport@echelon.com
London, U.K.
Tel: +44 192 343 0200
Fax: +44 192 343 0300
E-mail: lonsupport@echelon.co.uk
Your request for an RMA will require
the following information:
- Contact name and telephone number
- Company name
- Street address, city, postal code, country
- Product model number and/or description
- Quantity of units to be returned(by date code if at all possible)
NOTE!
Any PSG/2 or PSG-10 units that are returned must first have proprietary customer code removed before they are returned to Echelon.