78F0988 View Datasheet(PDF) - NEC => Renesas Technology

Part Name

Description

Manufacturer

78F0988

8-BIT SINGLE-CHIP MICROCONTROLLERS / 64 Pin

NEC => Renesas Technology 

µPD78F0988A, 78F0988A(A)

5. INTERNAL EXPANSION RAM SIZE SWITCHING REGISTER (IXS)

IXS is a register that sets the internal expansion RAM capacity by software setting. By using this register, the

memory of the µPD78F0988A and µPD78F0988A(A) can be mapped in the same manner as that of a mask ROM

version with a different internal expansion RAM capacity.

IXS is set with an 8-bit memory manipulation instruction.

IXS is set to 0CH by RESET input.

7

IXS 0

Figure 5-1. Format of Internal Expansion RAM Size Switching Register

6

5

4

3

2

1

0

Address After reset R/W

0

0 IXRAM4 IXRAM3 IXRAM2 IXRAM1 IXRAM0 FFF4H

0CH

R/W

IXRAM4IXRAM3 IXRAM2 IXRAM1 IXRAM0 Selection of internal

expansion RAM capacity

0

1

0

1

0 1024 bytes

0

1

1

Other than above

0

0 No internal expansion RAM

Setting prohibited

Table 5-1 shows the IXS setting values to make the memory mapping the same as that of mask ROM versions.

Table 5-1. Setting Value of Internal Expansion RAM Size Switching Register

Target Mask ROM Versions

µPD780982

µPD780983

µPD780984

µPD780986

µPD780988

IXS Setting Value

0CH

0AH

18

Data Sheet U15801EJ1V0DS

Share Link: