speed of core module address and data bus

Discussion to talk about hardware related topics only.
Post Reply
leetehui
Posts: 10
Joined: Thu Aug 27, 2009 2:50 am

speed of core module address and data bus

Post by leetehui »

I am using MOD5270B. When I use command memmove(), the clock speed of address and data bus to access external device is about 600 ns.
Can I make it faster? Which core module has the highest speed for external interface?
Robert Lee
National Synchrotron Radiation Research Center, Taiwan
User avatar
TomNB
Posts: 538
Joined: Tue May 10, 2016 8:22 am

Re: speed of core module address and data bus

Post by TomNB »

Hello, on the 5270 the bus speed is half the cpu core, which is 75MHz. That is the fastest bus.
User avatar
pbreed
Posts: 1080
Joined: Thu Apr 24, 2008 3:58 pm

Re: speed of core module address and data bus

Post by pbreed »

The speed issue is likely the speed to copy to DRAM....
Several things can be done to speed this up...
1)Have the destination in SRAM not DRAM...

Are you reading one address over and over or a range of addresses?
What is the bus width of your transaction?

Best to write out 32 bit chunks.

If the source and destination can both be 32 bit things..
void* memcpy(void *out, const void *in, size_t n)
has an assembly language routine backing it up that speeds up DRAM access, by doing reads, then writes in blocks...

If the source cna't be a 32 bit blocks then look at how memcpy in uconsmcfa.s is written...
and emulate that ..

If you can provide exact details of your bus transactions I can help you optimize.

IE what hardware are you reading from.
Port width.
Read from or write to addresses(one or a range)
Size of total blocks...
etc...
Post Reply