the 9914 mode is it available on TNT4882C?

[Charlu]

We are manufacturer of a measure instrument which uses the NI ASIC for its GPIB interface.

Our previous board used the NAT9914 Asic. We devellopped a new board with the TNT4882. Components that have been mounted on my prototype are (old) TNT4882C parts. I read, here, that the TNT4882C is full software compatible with the TNT4882. but, the 9914 mode is it available on TNT4882C? The component is in normal mode on hardware (Swap and mode no-connected). First, i reset the chip (write 22 in CMDR). The next command is to switch the device in 9914 mode (write 0x15 in AUXMR). After, the programm is the same as the NAT9914 version, without the sequence on 7210 mode to select frequency mode on NAT9914. But all the registers (ADR, ISR...) remain with FF ???  If i write the reset sequence with "one-ship" mode, as in the documentation, the component works, but i have to rewrite the entire software ! ...
Sorry for my english...

[Steven_T]

Charlu,

To answer your question, yes, the TNT4882C does have a mode that allows access to NAT9914 style registers.  I'm not sure what you mean in the rest of your description (But all the registers (ADR, ISR...) remain with FF ?).

What is your application (what instruments will contain this chip)?  Is there a reason why you do not want to use the TNT4882?

Steven T.

[Charlu]

Steven,
No, It there no reason to use the TNT4882c (our intrument is only device, no master). But, our purchaser recovered a stock of TNT4882C. I found here a discussion on the TNT4482C, which said that there was no problem : the TNT4882C works as the TNT4882. So,I say Ok for TNT4882C.
May be my problem is not the 'C', but a problem of init in 9914 mode... When i said that all registers remain with 0xFF (as ISR1 for example), it is the value read in the register after init sequence. The component don't work, and all status registers contain 0xFF. If i write the "One-Ship" init sequence, the registers contain good values. 
In 9914 mode, I tried with SWAP bit set (new map) and reset (9914 map) (write 0 or 0x40 in KCR before the switch to 9914 mode) : equal.
But, If you say that the 9914 mode is available in the TNT4882C, I will continue to seek, and certainly to find the small sand grain in my code…
Thanks a lot.
Charlu.