
MFC2000 Multifunctional Peripheral Controller 2000
Hardware Description
4-64
Conexant
100723A
Refresh
Speed:
(bit 5)
Oscillator
Speed:
(bit 4)
Refresh
Speed:
Description:
0
0
normal
RTC crystal frequency = 32.768 kHz,
Refresh clock = the crystal frequency = 32.768 kHz,
The refresh cycle time = 15.625 ms/1024 cycles.
0
1
fast
RTC crystal frequency = 65.536 kHz,
Refresh clock = the crystal frequency = 65.536 kHz,
Refresh cycle time = 7.8125 ms/1024 cycles.
1
0
slow
RTC crystal frequency = 32.768 kHz,
Refresh clock = the crystal frequency/8 = 4.096 kHz
Refresh cycle time = 125 ms/1024 cycles.
1
1
slow
RTC crystal frequency = 65.536 kHz,
Refresh clock = the crystal frequency/16 = 4.096 kHz
Refresh cycle time = 125 ms/1024 cycles.
Bits 3:
Bank 1 Enable
This bit controls whether or not the Bank 1 DRAMs will be enabled.
The Enable signal will allow CAS before RAS refresh to occur based
on the non-interleave or interleave setting. If the bank setting indicates
a non-interleaved mode, RASn[1] and CASOn[0] (8-bit mode) or
CASOn[1:0] (16-bit mode) will refresh the DRAM. If the bank setting
indicates an interleaved mode, RASn[1], CASOn[1:0] and CASEn[1:0]
will refresh the DRAM. DWRn will be high during refresh. If bank 1 is
disabled, RAS[1]n will be tri-stated and all appropriate CASn’s will be
tri-stated based on mode settings.
This bit controls whether or not the Bank 0 DRAMs will be enabled.
The Enable signal will allow CAS before RAS refresh to occur based
on the non-interleave or interleave setting. If the bank setting indicates
a non-interleaved mode, RASn[0] and CASOn[0] (8-bit mode) or
CASOn[1:0] (16-bit mode) will refresh the DRAM. If the bank setting
indicates an interleaved mode, RASn[0], CASOn[1:0] and CASEn[1:0]
will refresh the DRAM. DWRn will be high during refresh. If bank 0 is
disabled, RAS[0]n will be tri-stated and all appropriate CASn’s will be
tri-stated based on mode settings.
This register defines whether the bank 1 DRAMs are to be accessed
using 2-way interleave or non interleaved access. 2-way interleaved
access is only valid with a 16-bit interface (the 16 bit vs. 8 bit interface
size bit for bank 1 is ignored by the DRAM controller, but is used by
the SIU to output the data correctly).
This register defines whether the bank 0 DRAMs are to be accessed
using 2-way interleave or non interleaved access. 2-way interleaved
access is only valid with a 16-bit interface (the 16 bit vs. 8 bit interface
size bit for bank 1 is ignored by the DRAM controller, but is used by
the SIU to output the data correctly).
Bit 2:
Bank 0 Enable
Bit 1:
Bank 1 Interleave Enable
Bit 0:
Bank 0 Interleave Enable