SDRAM on EBU with XMC4700 using P5_8 as Clock

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
User18035
Level 1
Level 1
Hi, I'm facing a problem with sdram (IS42S16400 64mbit and IS42S16320 512mbit) on EBU with XMC4700 . If I select pin P6_4 as sdram clock it works like a charm, but if I choose P5_8 the MCU hang as soon as I try to read data from external memory.

Is there an errata about this or it's necessary to operate particular settings?

Thank you, regards.

Luca
0 Likes
3 Replies
User18035
Level 1
Level 1
Update: If I connect P5_8 as clock and define P6_4 as clock too ( without connecting it to sdram) all works without problem.

The waveform on P5_8 and P6_4 are the same...

Luca75
0 Likes
jferreira
Employee
Employee
10 sign-ins 5 sign-ins First like received
Hi,

From the reference manual:

SDRAM Clock Output/Input SDCLKO/SDCLKI
The EBU provides a clock output for SDRAM devices on the SDCLKO pin. SDCLKO is,
by default, a continuously running signal but can also be configured to switch off between
accesses to conserve power.
The feedback clock input, SDCLKI, is used as a timing reference for the capture of read
data on SDRAM accesses. It should be connected via a PCB trace to the clock pin of the
SDRAM device.


SDCLKI/SDCLKO (P6.4)
SDCLKO (P5.8)

If you use SDCLKO (P5.8), then you will need to connect externally to P6.4
If you use SDCLKO (P6.4), no external connection is needed. Every pin configured as output is at the same acting as input, sampling its output.
0 Likes
User18035
Level 1
Level 1
thank you, I assumed that the two pins had exactly the same characteristics...

Now I've only to remaster the pcb...

Regards,

Luca
0 Likes