Mitsubishi DS907x SIP, DS5000TK manual NON±PARTITIONABLE Memory MAP for DS5001, DS5002 Series ±6

USER'S GUIDE

Any address that does not fall into the Byte±wide bus area is routed to the Expanded bus of Ports 0 and 2. This could only occur for the first two settings. Note that a single 128K device is the least expensive in terms of component cost and size. In this case, all memory ad- dressable by the DS5001 is stored in a nonvolatile

128K x 8 SRAM. When the MSEL pin is grounded, the device automatically converts CE1 to a chip enable, CE2 to A16, CE3 to A15, and CE4 is unused. The MSL bit, accessible only via the bootstrap loader, is used to select whether the the 64KB data or 64KB program seg- ment is addressed by the loader.

NON±PARTITIONABLE MEMORY MAP FOR DS5001, DS5002 SERIES Figure 4±6

FFFFh

PES=0

64K

PROGRAM

RANGE

DATA

RANGE

7FFFh

32K

BYTE±WIDE

BUS ACCESS

BYTE±WIDE

BUS ACCESS

0000

PROGRAM	DATA
MEMORY	MEMORY

LEGEND:

=BYTE±WIDE ACCESS (NONVOLATILE RAM)

=EXPANDED BUS ACCESS ON PORTS 0 AND 2

DS5001/DS5002 Memory Mapped

Peripherals

The DS5001 series provides four decoded chip enables that can be used for peripheral access or extra RAM on the Byte±wide bus. Application software enables the

four PE signals, which are decoded on 16K byte bound- aries. While they are enabled, they completely use the data memory map and normal data memory is not avail- able on either the Byte±wide or Expanded bus. The PES bit (MCON.2) is set to a logic 1 to access the peripheral

space. When PES=1, the appropriate PE signal will be activated based on the logical address. Figure 4±7

shows the data memory map while PES=1. PES has an identical effect for either Partitionable or Non±partition- able modes. It has no effect on the program area. Note

that the first two Peripheral Enables, PE1 and PE2 are lithium backed by the DS5001. This means that when VCC is removed, the device will maintain these chip en-

ables in a logic high, inactive state. PE3 and PE4 are not lithium backed making them suitable for UARTs, A/Ds, etc. Lithium backed chip enables are used to access lithium backed memory or peripherals, including the DS1283 real±time clock used in the DS2251T and DS2252T.

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