Sdram Interface Configuration; Dcr Initialization; Initialization Values For Dcr; Sdram Hardware Connections - Motorola ColdFire MCF5281 User Manual

SDRAM Example

15.3.1 SDRAM Interface Configuration

To interface this component to the MCF5282 DRAM controller, use the connection table
that corresponds to a 32-bit port size with 8 columns (Table 15-24). Two pins select one of
four banks when the part is functional. Table 15-26 shows the proper hardware connections.
MCF5282 A15 A14
Pins
SDRAM Pins A0 A1

15.3.2 DCR Initialization

At power-up, the DCR has the following configuration if synchronous operation and
SDRAM address multiplexing are desired.
15 14 13
Field — — NAM COC
Setting
(hex)
This configuration results in a value of 0x0026 for DCR, as shown in Table 15-27.
Bits Name Setting
15 — 0
14 — 0
13 NAM 0
12 COC 0
11 IS 0
10–9 RTIM 00
8–0 RC 0x26
15.3.3 DACR Initialization
As shown in Figure 15-12, the SDRAM is programmed to access only the second
512-Kbyte block of each 1-Mbyte partition in the SDRAM (each 16 Mbytes). The starting
address of the SDRAM is 0xFF88_0000. Continuous page mode feature is used.
15-20
Table 15-26. SDRAM Hardware Connections
A13 A12 A11 A10
A2 A3 A4
12 11 10 9
IS RTIM
0000_0000_0010_0110
Figure 15-11. Initialization Values for DCR
Table 15-27. DCR Initialization Values
Reserved.
Reserved.
Indicating SDRAM controller multiplexes address lines internally
SCKE is used as clock enable instead of command bit because user is not multiplexing address lines
externally and requires external command feed.
At power-up, allowing power self-refresh state is not appropriate because registers are being set up.
Because t value is 70 ns, indicating a 3-clock refresh-to-
RC
Specification indicates auto-refresh period for 4096 rows to be 64 mS or refresh every 15.625 µs for
each row, or 625 bus clocks at 40 MHz. Because DCR[RC] is incremented by 1 and multiplied by 16,
RC = (625 bus clocks/16) -1 = 38.06 = 0x38
MCF5282 User's Manual
A9 A17 A18
A5 A6 A7 A8
8
0026
Description
A19 A20 A21
A9 A10 = CMD BA0
RC
timing.
ACTV
MOTOROLA
A22
BA1
0