Register 4: EPI SDRAM Configuration (EPISDRAMCFG), offset 0x010
Important: The MODE field in the EPICFG register determines which configuration register is
accessed for offsets 0x010 and 0x014.
To access EPISDRAMCFG, the MODE field must be 0x1.
The SDRAM Configuration register is used to specify several parameters for the SDRAM controller.
Note that this register is reset when the MODE field in the EPICFG register is changed. If another
mode is selected and the SDRAM mode is selected again, the values must be reinitialized.
The SDRAM interface is designed to interface to x16 SDR SDRAMs of 64 MHz or higher, with the
address and data pins overlapped (wire ORed on the board). See Table 11-3 on page 823 for pin
assignments.
EPI SDRAM Configuration (EPISDRAMCFG)
Base 0x400D.0000
Offset 0x010
Type RW, reset 0x82EE.0000
16171819202122232425262728293031
RFSHreservedFREQ
RWRWRWRWRWRWRWRWRWRWRWRORORORWRWType
0111011101000001Reset
0123456789101112131415
SIZEreservedSLEEPreserved
RWRWRORORORORORORORWROROROROROROType
0000000000000000Reset
DescriptionResetTypeNameBit/Field
EPI Frequency Range
This field configures the frequency range used for delay references by
internal counters. This EPI frequency is the system frequency with the
divider programmed by the COUNT0 bit in the EPIBAUDn register bit.
This field affects the power up, precharge, and auto refresh delays. This
field does not affect the refresh counting, which is configured separately
using the RFSH field (and is based on system clock rate and number of
rows per bank). The ranges are:
DescriptionValue
0 - 15 MHz0x0
15 - 30 MHz0x1
30 - 50 MHz0x2
50 - 100 MHz0x3
0x2RWFREQ31:30
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0x0ROreserved29:27
Refresh Counter
This field contains the refresh counter in EPI clocks. The reset value of
0x2EE provides a refresh period of 64 ms when using a 50 MHz EPI
clock.
0x2EERWRFSH26:16
863June 18, 2014
Texas Instruments-Production Data
Tiva
™
TM4C1294NCPDT Microcontroller
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