UPD705100 Datasheet, PDF (13/66 Pages) NEC – V830TM 32-BIT MICROCONTROLLER

µPD705100
3. 32-BIT BUS MODE
If the SIZ16B input, sampled at reset, is inactive, the external bus width becomes 32 bits (32-bit bus mode). In
this mode, BE2/BH acts as BE2 and BE3/A1 acts as BE3.
3.1 Relationship between External Accesses and Byte Enable Signals
In 32-bit bus mode, BE0-BE3 are output. External accesses are related to byte enable signals as indicated below.
Table 3-1. 32-Bit Bus Mode
Data length
Operand address
Byte enable
State
Bit 1
Bit 0
BE3
BE2
BE1
BE0
Byte
0
0
1
1
1
0
Ta,Ts
0
1
1
1
0
1
Ta,Ts
1
0
1
0
1
1
Ta,Ts
1
1
0
1
1
1
Ta,Ts
Halfword
0
0
1
1
0
0
Ta,Ts
1
0
0
0
1
1
Ta,Ts
Word
0
0
0
0
0
0
Ta,Ts
Burst transfer
0
0
0
0
0
0
Ta,Tb1
0
0
0
0
0
0
Tb2
0
0
0
0
0
0
Tb3
0
0
0
0
0
0
Tb4
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