Can't disable autostore on CY14B108N?

[Anonymous]

Hi,

   

I am having difficulty sending software controlled autostore disable.  I think I am interpreting the datasheet reads incorrectly. Is there a more detailed document regarding the software commands?

   

The data sheet states that sequential reads of 0x4e38, 0xb1c7, 0x83e0, 0x7c1f, 0x703f, 0x8b45.  The CY14B108N has 19 address pins while there are only 16 pins defined with these hex address. 

   

I have assumed that A18,A17,A16 are set to zero and not used.

   

A15            -              A0  <-address bits used

   

0100 1110 0011 1000 <- binary first read

   

    4       E      3        8    <- First read

   

Thus,

   

(A15 = 0, A14=1, A13=0, A12=0) = 4xh

   

(A11=1, A10=1, A9=1, A8=0) = Exh

   

etc.....

   

This should be straight forward, but I notce there is small print in datasheet under truth table that states.....

   

6. While there are 20 address lines on the CY14B108L (19 address lines on the CY14B108N), only the 13 address lines (A14–A2) are used to control software modes.
Rest of the address lines are don’t care.

   

Again, there are 16 bits defined in the hex value but now with this statement only 12 bits matter?

   

Can someone please explain this?

   

I have attached waveform of the 6 reads, does this look correct?

   

Thanks,

   

Rad

[Anonymous]

I found document that states to maintain software autostore disable after power down, you must also issue a software store sequence before power down.  I will attempt this and report back.

[AjayB_76 · Accepted solution]

Hi Rad,

   

I can explain about the soft sequence commands:

   

a) Only 13 address lines matter for the soft sequence commands.

   

E.g. for the command specified as address location 0x4E38

   

0100  1110  0011  1000)

   

   4         E      3        8   

   

Only the address lines number (A2-A13) matter and should have the values specified above.

   

That means that even if a read from another location where A14=0 and A15=1 and A0=1 (i.e 0x8E39 instead of 0x4E38 is treated as a  soft sequence initiation command)

   

1000 1110 0011 1001

   

8        E       3        9

       

b) Yes, to disable AutoStore after a sequence for disabling AutoStore is complete, a software store or a HSB store has to be initiated. This saves the state of AutoStore disable and from the next power cycle, Autostore will be disabled.

   

If SoftwareStore or HSB Store is not done after disabling AutoStore, then from the next power cycle AutoStore will not be disabled.

[Anonymous]

Thank you ajai for the response.  With the correct data input defined I could look elsewhere.

   

I found that most of my problems were due to HSB pin acidentally droppping low between tests and causing hardware store at wrong time.  

   

Thanks for the help,

   

Rad

[AjayB_76]

Hi Rad,

   

No problems, good luck for your design.