Panasonic F77G Bank Function, Bank Setting, Address Range, Bank area Address range DBA1 DBA0

Models: F77G MN101C77C

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Chapter 2 CPU Basics

2-6 Bank Function

2-6-1 Overview

CPU of MN101C00 series has basically 64 KB memory address space. On this LSI, address space can be expanded up to 4 banks (256 KB) based on units of 64 KB, by bank function.

2-6-2 Bank Setting

Bank function can be used by setting the proper bank area to the bank register for source address (SBNKR) or the bank register for destination address (DBNKR). At reset, both of the SBNKR register and the DBNKR register indicate bank 0. Bank function is valid after setting any value except "00" to the SBNKR register or the DBNKR register.

When the both registers of SBNKR and DBNKR are operated at interrupt processing, pushing onto the stack or popping are necessary.

 

Table 2-6-1

Address Range

 

 

 

 

 

SBA1

SBA0

Bank area

Address range

(DBA1)

(DBA0)

 

 

 

 

 

 

 

 

0

0

 

Bank 0

x'00000' to x'0FFFF'

 

 

 

 

 

0

1

 

Bank 1

x'10000' to x'1FFFF'

 

 

 

 

 

1

0

 

Bank 2

x'20000' to x'2FFFF'

 

 

 

 

 

1

1

 

Bank 3

x'30000' to x'3FFFF'

 

 

 

 

 

When bank area is changed at interrupt processing, pushing onto the stack or popping must be done by program, if it necessary.

The stack area should be set in the area of bank 0, always. Furnished C compiler does not support bank function.

During bank function is valid, I/O short instruction should be used for access to the special function register area (x'03F00' to x'03FFF'). For access to the memory space x'13F00' to x'13FFF', x'23F00' to x'23FFF' and x'33F00' to x'33FFF', both instructions of register indirect

and register relative indirect should be used. [

Chapter 2 2-1-8. Addressing Modes]

Bank Function

II - 27

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Panasonic F77G, MN101C77C user manual Bank Function, Bank Setting, Address Range, Bank area Address range DBA1 DBA0