SDC Register Definitions
6-60
ADSP-BF537 Blackfin Processor Hardware Reference
SDC Register Definitions
The following sections describe the SDC registers.
EBIU_SDRRC Register
The SDRAM refresh rate control register (
EBIU_SDRRC
, shown in
) provides a flexible mechanism for specifying the auto-refresh
timing. Since the clock supplied to the SDRAM can vary, the SDC pro-
vides a programmable refresh counter, which has a period based on the
value programmed into the
RDIV
field of this register. This counter coordi-
nates the supplied clock rate with the SDRAM device’s required refresh
rate.
The desired delay (in number of SDRAM clock cycles) between consecu-
tive refresh counter time-outs must be written to the
RDIV
field. A refresh
counter time-out triggers an auto-refresh command to all external
SDRAM devices. Write the
RDIV
value to the
EBIU_SDRRC
register before
the SDRAM powerup sequence is triggered. Change this value only when
the SDC is idle.
To calculate the value that should be written to the
EBIU_SDRRC
register,
use the following equation:
RDIV
= ((f
SCLK
×
t
REF
) / NRA) – (t
RAS
+ t
RP
)
= (f
SCLK
×
t
REFI
) - (t
RAS
+ t
RP
)
Figure 6-14. SDRAM Refresh Rate Control Register
15 14
13 12
11 10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
1
0
1
SDRAM Refresh Rate Control Register (EBIU_SDRRC)
RDIV[11:0]
Reset = 0x081A
0xFFC0 0A18
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...