mcf5407 Freescale Semiconductor, Inc, mcf5407 Datasheet - Page 274

• Manufacturer Part Number: mcf5407
• Description: Mcf5407 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

Asynchronous Operation
Table 11-4 describes DACRn fields.
11-6
Reset
31–18
17–16
13–12
11–10
Field
Addr
Bits
R/W
15
14
9
8
7
6
31
RNCN RAS-negate-to-CAS-negate. Controls whether RAS and CAS negate concurrently or one clock
Name
CAS
RCD
EDO
Figure 11-3. DRAM Address and Control Registers (DACR0/DACR1)
BA
RE
RP
—
—
—
Base address. Used with DMR[BAM] to determine the address range in which the associated
DRAM block is located. Each BA bit is compared with the corresponding address of the bus cycle in
progress. If each bit matches, or if bits that do not match are masked in the BAM, the address
selects the associated DRAM block.
Reserved, should be cleared.
Refresh enable. Determines whether the DRAM controller generates a refresh to the associated
DRAM block. DRAM contents are not preserved during hard reset or software watchdog reset.
0 Do not refresh associated DRAM block. (Default at reset)
1 Refresh associated DRAM block.
Reserved, should be cleared.
CAS timing. Determines how long CAS is asserted during a DRAM access.
00 1 clock cycle
01 2 clock cycles
10 3 clock cycles
11 4 clock cycles
RAS precharge timing. Determines how long RAS is precharged between accesses. Note that RP
is different from DCR[RRP].
00 1 clock cycle
01 2 clock cycles
10 3 clock cycles
11 4 clock cycles
apart. RNCN is ignored if CAS is asserted for only one clock and both RAS and CAS are negated.
RNCN is used only for non-page-mode accesses and single accesses in page mode.
0 RAS negates concurrently with CAS.
1 RAS negates one clock before CAS.
RAS-to-CAS delay. Determines the number of system clocks between assertions of RAS and CAS.
0 1 clock cycle
1 2 clock cycles
Reserved, should be cleared.
Extended data out. Determines whether the DRAM block operates in a mode to take advantage of
industry-standard EDO DRAMs. Do not use EDO mode with non-EDO DRAM.
0 EDO operation disabled.
1 EDO operation enabled.
Unitialized
BA
Table 11-4. DACR0/DACR1 Field Description
18 17 16
MBAR + 0x10C (DACR0); 0x110 (DACR1)
—
MCF5407 User’s Manual
RE — CAS
15
0
14 13 12 11 10
R/W
Description
RP
RNCN RCD — EDO
9
Unitialized
8
7
6
5
PS
4
3
PM
2
1
—
0