Does the MOD5234 need a buffer for data lines D16-D31 ?

[seulater]

I know when using the mod5270's Address / Data bus one should use a line buffer for signals D16-D31. I have been poking around the MOD5234 web page and looking through data sheets and I have not yet found anything that says the MOD5234 needs the same thing.
Would someone from NB please let me know if I am using D16-D31 on the MOD5234 do I "NEED" to use a buffer ?

[Ridgeglider]

seulater:
I built a 5234 bus interface to the max197 (the same AD used on the PK70 multifuncton.)
I used a 72VL245 buffer and the hardware & code setup below. Worked fine.

I connected 5234 D[24..31] to B[0..7] of the 74VL245, then:
5234 *TIP to '245 OE
5234 R/*W to '245 DIR

On the Max197:
'245 A[0..7] to '197 D[0..8]
5234 A0 to '197 HBEN
5234 *OE to '197 *RD
5234 R/*W to '197 *WR
5234 *CS1 to '197 *CS
5234 DTOUT to '197 CLK


Code setup:
(paste the following into eclipse editor and it looks correct)
InitNonISR2MhzDTOUT0SquareWaveForADCLK();
sim.cs[1].csar = ( BASEADDRESS >> 16 ); //CSAR = 0x0220, ext mem starts at
// 0x0220_0000
//Setup CSCR:===========================================================
//SWWS- 2ndary writes disabled for writes--------------------------|
//BSTW- Write data in Bytes------------------------------------| |
//BSTR- Read data in bytes-----------------------------------| | |
//BEM - Byte enabled mode, *BS asserted for RD & WR access-| | | |
//PS - Port Size = 8, valid data on D[31:24]------------| | | | |
//AA - Auto Acknowledge Enabled----------------------| | | | | |
//Reserved keep CLR---------------------------------| | | | | | |
//IWS - 8 wait states-----------------------------| | | | | | | |
//SRWS - disabled for reads------------------| | | | | | | | |
// | | | | | | | | |
// -- ---- | | -- | | | ---
sim.cs[1].cscr = 0x2140; // 00 1000 0 1 01 1 0 0 000

//Setup CSMR:===========================================================

sim.cs[1].csmr = 0x00000001; // BAM field = 0x0000: CS 2^(0+16)
// sim.cs[1].csmr = 0x000001; // = 64K byte block
pAtoD = ( PBYTE ) BASEADDRESS;

[seulater]

Thanks for the detail !!!

But what I want to know is if I really need to even use the buffer. I know there is documentation for the MOD5270 to use it, however I was unable to find a recommendation to use it for the MOD5234. I have it working now without it, but we are redoing the PCB and if I should then I want to add it on now.

[rnixon]

SDRAM in general usually has very low drive capability. The bus buffer solves this problem, even if the coldfile doesn't need it. If you are only driving one gate you are "probably" ok, but you need to make the decision knowing that you are assuming some risk.