Revision 1.7 Page 25 of 27
09/12/1999
Appendix C - The Most Commonly Asked I2C Questions
General Questions
Question Will my adapter work in a Pentium PC?
Answer Yes and there is no need to alter LK 4 from the position in which your adapter was shipped.
Question Will my adapter run I2C clock speeds greater than 90KHz?
Answer At the mom ent your adapter is limited by the Bus Controller chip fitted, to a max imum of 90KHz
as a master and 100KHz as a slave.
Question Will my adapter work under Windows NT4* or Windows 95*?
Answer The adapter will work under both these systems without problems, but the software
supplied with the adapter is 16 bit only. Windows NT and Windows 95 DLLs are available
please contact our sales team for further information.
The bus monitors are best run from DOS (not Windows DOS Shell) as this minimises the risk of
missing part of a transfer.
* All trade marks acknowledged
Question How can I find out if the adapter is clashing with another card in my PC?
Answer If your adapter is located at a base address of 310H (as shipped) then run the bus
monitor (REALTIM1) application supplied following the instructions in the adapter
manual. With no activity on the bus the monitor should display a fix 'A', stop the monitor
and edit the file produced if the file states that the bus was free and the status was 81H
then your adapter is indeed located at 310H and there are no clashes within the PC.
If your adapter is at 312H then repeat the above using the REALTIM2 bus monitor.
Question I get corrupted transfers why is this?
Answer The most likely reason for corrupted transfers is either incorrect bus termination or
excessive capacitance - see the manual for details.
Question Do you have software to talk to my........?
Answer Unfortunately there are too many I2C devices for us to be able to offer complete solutions
- although we can supply a windows based application called WINI2C which is designed
for those just starting I2C or wishing to perform simple I2C tasks, please contact our
sales team or look on our web site, www.calibreuk.com for further information.
Question I am trying to read from a device, the first time my software works fine but when I
try again I can't get anything what's wrong?
Answer Please check that you are changing the value of Setnack in accordance with the manual,
it is likely that you have not made Setnack 1 for the last AND last but one bytes being
read.
DOS Software Questions
Question My I2C adapter locks up with a constant status - why?
Answer If you are using either the 'C' or Basic library functions supplied with the adapter on a fast
PC it is possible that the PC is polling the status register too quickly, the simplest way to
prevent this is to add a small delay prior to reading the status in the getstatus routine.
Alternatively use the windows DLL supplied as these automatically allow for speed of the
PC at run-time.
Windows 95 and NT Questions
Question My software cannot find the adapter. Your Windows software reports that it cannot
configure the adapter. Why is this?
Answer Have you registered the device driver as detailed in the software manual? If so check that
the address links (see adapter manual for details) are correct for the location at which
you registered the driver.
Question I think I have registered the driver how can I find out if I have?
Answer You need to inspect the registry as follows