USER'S GUIDE

DS5000 SERIES MEMORY MAP Figure 4±3

FFFFh

7FFFh

1FFFh

PARTITION

ADDR.

0000

BYTE±WIDE

BUS ACCESS

ECE2=0

BYTE±WIDE

BUS ACCESS

ECE2=1

64K

ÑÑÑÑ32K8K

BYTE±WIDE

BUS ACCESS

RANGE

ADDR.

LEGEND:

PROGRAM

DATA

MEMORY

MEMORY

 

DEVICE #1 SELECTED

 

WITH CE1

DATA

MEMORY

DEVICE #2 SELECTED

WITH CE2

=NO MEMORY ACCESS

=BYTE±WIDE ACCESS WITH CE2 (NONVOLATILE RAM)

BYTE±WIDE ACCESS WITH CE1

=(NONVOLATILE RAM)

=EXPANDED BUS ACCESS ON PORTS 0 AND 2

The above memory map covers the standard operating case. There are two conditions that can modify this

memory map. The first is the EA pin. The second is the

Security Lock. When the EA pin is grounded, the DS5000 will force all memory access to the Expanded bus. This causes the DS5000 to behave like an 8031 re-

gardless of the Partition, Range, or ECE2. The EA should be pulled to +5V for normal operation. The se- cond modifier is the Security Lock. When set, the Secu- rity Lock prevents using the Bootstrap Loader to read the contents of the NV RAM. For security purposes, it also prohibits program memory access on the Expand- ed Bus. Thus all program fetches must be restricted to the Byte±wide bus when locked. The Security Lock

overrides the condition of the EA pin as well.

The selection of memory map controls provide unprec- edented flexibility to configure a system. However, it is possible to select contradictory settings. The micro will compensate for these as follows. The Partitioning func- tion allows a user to select the quantity of program and data memory. It is possible to select all data and no pro- gram in NV RAM by choosing a Partition of 0000h. This is a valid selection. However, using this setting and the Security Lock is a conflict. This condition asks the micro to use all program memory on the Expanded bus, but also to prohibit the use of program memory on the Ex- panded bus. In this event, special circuits will automati- cally force the Partition to a location of 7FFFh. This means all 32K memory on the Byte±wide bus is desig- nated program memory. The second contradictory

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Mitsubishi DS5000TK, DS907x SIP manual DS5000 Series Memory MAP ±3, Memory map. The first is the EA pin. The second is