UPD754304GS datasheet(39/74 Pages) NEC

39 / 74 page

µPD754302, 754304, 754302(A), 754304(A)

(3) Explanation of symbols under addressing area column

MB = MBE•MBS

(MBS = 0, 15)

MB = 0

MBE = 0 : MB = 0 (000H-07FH)

MB = 15 (F80H-FFFH)

Data memory addressing

MBE = 1 : MB = MBS (MBS = 0, 15)

MB = 15, fmem = FB0H-FBFH, FF0H-FFFH

MB = 15, pmem = FC0H-FFFH

µPD754302

addr = 0000H-07FFH

µPD754304

addr = 0000H-0FFFH

addr

= (Current PC) – 15 to (Current PC) – 1

(Current PC) + 2 to (Current PC) + 16

addr1 = (Current PC) – 15 to (Current PC) – 1

(Current PC) + 2 to (Current PC) + 16

µPD754302

caddr = 0000H-07FFH

Program memory addressing

µPD754304

caddr = 0000H-0FFFH (PC12 = 0)

faddr = 0000H-07FFH

*10

taddr = 0020H-007FH

*11

µPD754302

addr1 = 0000H-07FFH

µPD754304

addr1 = 0000H-0FFFH

Remarks 1.

MB indicates memory bank that can be accessed.

In *2, MB = 0 independently of how MBE and MBS are set.

In *4 and *5, MB = 15 independently of how MBE and MBS are set.

*6 to *11 indicate the areas that can be addressed.

(4) Explanation of number of machine cycles column

S denotes the number of machine cycles required by skip operation when a skip instruction is executed.

The value of S varies as follows.

• When no skip is made: S = 0

• When the skipped instruction is a 1- or 2-byte instruction: S = 1

• When the skipped instruction is a 3-byte instruction Note: S = 2

Note 3-byte instruction: BR !addr, BRA !addr1, CALL !addr or CALLA !addr1 instruction

Caution The GETI instruction is skipped in one machine cycle.

One machine cycle is equal to one cycle of CPU clock (= tCY); time can be selected from among four types

by setting PCC.

UPD754304GS Datasheet(PDF) 39 Page - NEC

UPD754304GS Datasheet(HTML) 39 Page - NEC

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