Digi NS9750 User Manual

Page 230

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R e g i s t e r s

2 0 6

N S 9 7 5 0 H a r d w a r e R e f e r e n c e

D01

R/W

ADDM

Address mirror

0

Normal memory map

1

Reset memory map. Static memory chip select 1 is mirrored
onto chip select 0 and chip select 4 (reset value on

reset_n

)

Indicates normal or reset memory map. On power-on reset, chip
select 1 is mirrored to both chip select 0 and chip select 1/chip select
4 memory areas. Clearing the M bit allows chip select 0 and chip
select 4 memory to be accessed.

D00

R/W

MCEN

Memory controller enable

0

Disabled

1

Enabled (reset value on

reset_n

and

HRESETn

)

Disabling the memory controller reduces power consumption. When
the memory controller is disabled, the memory is not refreshed. The
memory controller is enabled by setting the enable bit, by AHB, or
by power-on reset.

If you modify this bit, be sure the memory controller is in idle state.

If you modify the E bit, be aware of these conditions:

The external memory cannot be accessed in low-power or

disabled state. If a memory access is performed in either of
these states, an error response is generated.

The memory controller AHB programming port can be

accessed normally.

The memory controller registers can be programmed in low-

power and/or disabled state.

Bits

Access

Mnemonic

Description

Table 138: Control register

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