Motorola MCF5282 Dram Address and Control Registers DACR0/DACR1, 5describes DACRn fields, Bit

SDRAM Controller Operation

15.2.2.2DRAM Address and Control Registers (DACR0/DACR1)

The DACRn registers, shown in Figure 15-3,contain the base address compare value and the control bits for memory blocks 0 and 1 of the SDRAM controller. Address and timing are also controlled by bits in DACRn.

Field

Reset

R/W Address

31	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	0
BA		—		RE	—	CASL		—	CBM			—	IMRS	PS		IP		—
Uninitialized				0			Uninitialized						0		Uninitialized

R/W

IPSBAR+0x048 (DACR0); 0x050 (DACR1)

Figure 15-3. DRAM Address and Control Register (DACRn)

Table 15-5describes DACRn fields.

							Table 15-5. DACRn Field Descriptions
Bit	Name							Description
31–18	BA		Base address register. With DCMR[BAM], determines the address range in which the associated DRAM block is
			located. Each BA bit is compared with the corresponding address of the current bus cycle. If all unmasked bits
			match, the address hits in the associated DRAM block. BA functions the same as in asynchronous operation.
17–16	—	Reserved, should be cleared.
15	RE		Refresh enable. Determines when the DRAM controller generates a refresh cycle to the DRAM block.
			0 Do not refresh associated DRAM block
			1 Refresh associated DRAM block
14	—		Reserved, should be cleared.
13–12	CASL				latency. Affects the following SDRAM timing specifications. Timing nomenclature varies with
			CAS
			manufacturers. Refer to the SDRAM specification for the appropriate timing nomenclature:
							Parameter			Number of Bus Clocks
									CASL= 00	CASL = 01	CASL= 10	CASL= 11
				tRCD—SRAS		assertion to SCAS assertion			1	2	3	3
							assertion to data out		1	2	3	3
				tCASL—SCAS
				tRAS—ACTVcommand to precharge command					2	4	6	6
				tRP—Precharge command to ACTV command					1	2	3	3
				tRWL,tRDL—Last data input to precharge command					1	1	1	1
				tEP—Last data out to precharge command					1	1	1	1
11	—		Reserved, should be cleared.

15-6 MCF5282 User’s Manual MOTOROLA