Sharp LH79524 - Configuration Register (CONFIG); Table 7-15. CONFIG Register; Table 7-16. CONFIG Fields

External Memory Controller LH79524/LH79525 User’s Guide
7-32 Version 1.0
7.5.2.3 Configuration Register (CONFIG)
The CONFIG Register configures the operation of the memory controller.
This register must only be modified during system initialization, or when there are no cur-
rent or outstanding transactions. Software can ensure that there are no current or out-
standing transactions by waiting until the memory controller is idle, then entering Low-
Power Mode (CONTROL:MODE = 1), or Disable Mode (CONTROL:ENABLE = 0). When
in these two modes, external memory access is not allowed, ensuring that changing
parameters will not corrupt external data. Low-Power Mode automatically refreshes
SDRAM; Disable Mode requires commanding the SDRAM to Self Refresh (DYNMC-
TRL:SR = 1) prior to entering Disable.
Table 7-15. CONFIG Register
BIT 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
FIELD ///
RESET 0000000000000000
TYPE RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO
BIT 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
FIELD /// CLK ///
RESET 0000000000000000
TYPE RO RO RO RO RO RO RO RW RW RW RW RW RW RW RW RW
ADDR 0xFFFF1000 + 0x008
Table 7-16. CONFIG Fields
BITS NAME FUNCTION
31:9 /// Reserved Reading returns 0. Write the reset value.
8CLK
HCLK to SDCLK Ratio
1 = RESERVED; program to 0
0 = 1:1
7:0 /// Reserved Reading returns 0. Write the reset value.