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About behavior of the CS with the DTACK mode of i.MX6

Question asked by yuuki on Jul 9, 2017
Latest reply on Jul 11, 2017 by Yuri Muhin

Dear all,


We have a problem that CS is negated before DTACK signal is asserted.


We got the following answer before.
 "CS assertion period is extended for DTACK wait period"


However, there is the case that CS is negated befor DTACK singal is asserted.
(at both a Read access and a Write access)
And the communication with the external device becomes the error.
(An iMX6_WDT time out error occurs.)


About 10 systems of 200 systems have this problem.


We suspect that register setting may not be right.
We do not understand the cause of this problem.


A register dump is the following.

<Address>    <Register name>    <Setting value>
0x20E01E0    IOMUXC_SW_MUX_CTL_PAD_EIM_WAIT_B    0x00000001
0x21B8000    EIM_CS0GCR1    0x00020001
0x21B8004    EIM_CS0GCR2    0x00000100
0x21B8008    EIM_CS0RCR1    0x06000302
0x21B800C   EIM_CS0RCR2    0x00000002
0x21B8010    EIM_CS0WCR1   0x09003003
0x21B8014    EIM_CS0WCR2   0x00000000


RFL=0 / WFL=0 / MUM=0 / SRD=0 / SWR=0

DAP=0 / DAE=1 / DAPS=0000


May I have any advice?


It is a product under production, and it is necessary to correct it immediately.
Your kind helps would be greatly appreciated.


Best Regards,