Jameco Electronics 3000, 2000 manual B.1.7 RAM Segment Relocation, Table B-15.RAM Segment Register

Models: 3000 2000

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B.1.7 RAM Segment Relocation

B.1.7 RAM Segment Relocation

Normally when instruction/data separation is enabled, instructions are stored in flash memory and data are stored in RAM memory. This can present a problem for the Interrupt Service Routine area, which often requires run-time modification. The RAM Segment Register (RAMSR) allows a 1, 2, or 4 KB segment of the logical memory space to be mapped as data would be mapped, even for program execution.

Table B-15. RAM Segment Register

 

RAM Segment Register

(RAMSR)

(Address = 0x0448)

 

 

 

 

 

 

Bit(s)

 

Value

 

Description

 

 

 

 

 

 

7:2

 

 

Compare value for RAM segment limit checking.

 

 

 

 

 

 

1:0

 

00

Disable RAM segment limit checking.

 

 

 

 

 

 

 

01

Select data-type MMU translation if PC[15:10] is equal to RAMSR[7:2].

 

 

 

 

 

 

10

Select data-type MMU translation if PC[15:11] is equal to RAMSR[7:3].

 

 

 

 

 

 

11

Select data-type MMU translation if PC[15:12] is equal to RAMSR[7:4].

 

 

 

 

 

 

User’s Manual

291

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Jameco Electronics 3000, 2000 manual B.1.7 RAM Segment Relocation, Table B-15.RAM Segment Register