USER'S GUIDE

DS5001/DS5002 SERIES RPCTL REGISTER BITS AFFECTING MEMORY Figure 4±9

RNR

±±±

EXBS

AE

IBI

DMA

RPCON

RG0

Bit Description:

RPCTL.5:

EXBS

 

The Expanded Bus Select routes data memory access (MOVX) to the

 

Expanded bus formed by ports 0 and 2 when set.

Initialization:

Cleared after all resets.

Read Access:

Can be read at any time.

Write Access:

Can be written at any time.

RPCTL.4:

AE

 

Access Enable is used when a software reload is desired without using

 

Program Load mode. When set, the DS5001 will be temporarily configured

 

in a Partitionable configuration with the partition at 4K. This will occur even

 

if the PM=1. When cleared, the prior memory configuration is resumed.

Initialization:

Cleared after all resets.

Read Access:

Can be read at any time.

Write Access:

Can be written at any time, timed access protected.

RPCTL.0:

RG0

 

This is a Range bit which is used to determine the size of the program

 

memory space. Its usage is shown above.

Initialization:

Unaffected by watchdog, external, or power±up resets. Cleared on a No VLI

 

reset or clearing of the security lock.

Read Access:

Can be read at any time.

Write Access:

Cannot be modified by the application software. Can only be written during

 

Program Load.

Loading and Reloading Program Memory

device, the Bootstrap Loader must be invoked. Howev-

Soft Microcontrollers are programmed through a built±

er, the Secure Microcontroller is designed to allow a

in Bootstrap Loader function. This loader is also used to

partial reload of memory without invoking the Bootstrap

configure the desired options for memory map control.

Loader.

The Secure Microcontroller uses its low power lithium

 

backed circuits to maintain critical settings in the ab-

The major advantage of this technique is that it requires

sence of power. For this reason, it is not necessary to set

no hardware or external switches. Most of the memory

the Partition, Range, etc. after every power±up or reset.

can be reprogrammed under application software con-

Once set, they will remain unless deliberately modified.

trol. It would commonly be used when the target system

Bootstrap Loading is discussed in a later section. One

connects to a PC through a serial port as part of an ap-

of the major advantages of a Secure Microcontroller is

plication. For example, a data logger that must dump

the ability to change these settings, and even reload the

memory periodically. While connected to the PC, it is

entire program memory while the device is installed in

extremely easy to reload portions of memory using the

system. To completely re±program and re±configure a

ªSoft Reloadº.

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Mitsubishi DS5000TK, DS907x SIP manual Loading and Reloading Program Memory, RPCTL.5 Exbs, RPCTL.4, RPCTL.0 RG0