Other Parts Discussed in Thread: C2000WARE
Hello there,
We're trying to get a 10ns SRAM( ISSI IS64WV25616BLL-10CTL ) working at the highest possible frequency with the 320F28377D EMIF1. Considering that the EMIF clock can be set to be equal with thew CPU clock, that is 200MHz, we were hoping to achieve somewhere around 20 ns read/write cycles but on our custom designed board the NEM1CS3, NEM1WE and NEM1OE signals need about 50ns to switch from 3.3V to less than 0.4V for a logic "0" and about the same for the rising edge. In order to ensure the SRAM will be able to detect a correct low level (< 0.4V) I had to set the RSTROBE and WSTROBE to 11 (55ns) which is much slower that what we would expect.
On our board the hardware designers used a 33 ohms in series with all control, address and data lines connecting the DSP with the SRAM, the longest trace is about 4 cm.
For comparison I tried running the "emif1_16bit_asram_cpu0" project provided in the C2000Ware_1_00_01_00\device_support\f2837xd\examples on the F2837x controlCARD v1.3 board (without actually having the SRAM connected to the DSP) and noticed that without any load the NEM1CS3, NEM1WE and NEM1OE signals need about 35-40ns for switching from high to low and the same for low to high.
Except for adding signal buffers is it possible to speed up the 320F28377D external memory interface?
Thanks a lot,
Doru
