External Memory Timing - Spectrum Digital eZdsp R2812 USB Technical Reference

2.2.2 External Memory Timing

This section describes the timing for the external memory bus when the R2812 is
operating at 150 Mhz. In addition a segment of 'C' code is provided to configure the
EMIF.
The following 'C' code segment will initialize the EMIF for 150 Mhz operation.
#define XINTCNF2 ( 0x13 )
#define XWRTRAIL(x)
#define XWRACTIVE(x)
#define XWRLEAD(x)
#define XRDTRAIL(x)
#define XRDACTIVE(x)
#define XRDLEAD(x)
#define USEREADY
#define ASYNCREADY (1<<15)
#define XTIMING6 (XWRTRAIL(2)
XINTF_Init()
{
*(unsigned long *)0xB2C = (unsigned long)XTIMING6;
*(unsigned long *)0xB34 = (unsigned long)XINTCNF2;
}
Table 2: External Memory Timing
Memory
Time in ns.
Function
Write Cycle Time
Write Low Time
Write High Time
Read Cycle Time
Read Low Time
Read High Time
((x & 3))
((x & 7)<<2)
((x & 3)<<5)
((x & 3)<<7)
((x & 7)<<9)
((x & 3)<<12)
(1<<14)
| \
XWRACTIVE(1) | \
XWRLEAD(2) | \
XRDTRAIL(2) | \
XRDACTIVE(3) | \
XRDLEAD(2) )
Spectrum Digital, Inc
40.4ns
14.0ns
26.4ns
60.8ns
26.8ns
34.0ns
2-5