XMC4500, DAV4: Problem with Pin Assignment USIC-Module IIC and CAN

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User10538
Level 3
Level 3
Hello,

I'm using the XMC4500-F144K1024 AB with DAVE4.
I have only the IIC-Master App and its dependancies in the project, and want to use the USIC2-Module, CH1.

According the xmc4500_reference_manual_v1.5_2014_07 on page 1815 you'll find USIC2_CH1.SCLKOUT is assignable to the Pins 3.6; 3.13 and 4.2. However when I select the Manual Pin Allocator in Dave I only get the option to select 3.6 or 4.2.
The same goes for the SDA-options: I only get P3.5 but should also be able to use 3.4; 4.0 and 3.12 if I check in the reference manual on page 1811.

Due to constraints in my design I need to use the Pins 3.12 and 3.13.
Is this possible?
Is there an error in the reference manuals or the dave app pin selector or do I just understand the reference manual wrong? please explain.

Similar Problem with CAN:
Can't assign P1.5 N1_TXD, it's also missing from the selection list.


Regards,
Andy
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1 Reply
chismo
Employee
Employee
First like received
Hello Andy,

The IIC protocol requires bidirectional pins for both SDA and SCL.
This means that ideally, the selected SDA pin needs to have both the USIC input DX0 and output DOUT0 functions, which in this case is only the pin P3.5.
Similarly, the selected SCL pin needs both DX1 and SCLKOUT functions, i.e. pins P3.6 or P4.2.
The above are offered by the DAVE tool.

Nevertheless, it is possible to select pins other than the above such as P3.11 for SDA output but you will need to also connect it externally to one of the DX0 pins (P3.5, P3.4, P4.0, P3.12).
You will also need to manually override the DAVE pin selection in your software.
The same idea applies for SCL, i.e. P3.13 (SCLKOUT) has to be externally connected to one of the DX1 pins (either P3.6 pr P4.2).

Regards,
Min Wei
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