W78958B Datasheet, PDF (4/28 Pages) Winbond – 8-BIT EMULATION MICROCONTROLLER

W78958B
PIN DESCRIPTION
ENSTD Enable Standard Type, Input, Active Low
TYPE
MODE
DESCRIPTION
Advanced
-
Default status is pulled high by internal pull-up resistor.
Standard
-
A low on this pin enables the standard type.
Note: "-" in "Mode" column means that the function description is valid in both modes, normal and emulation.
EA External Address, Input
TYPE
MODE
DESCRIPTION
Advanced
-
Functions same as in W78C438.
Standard
-
Functions same as in W78C51, W78C52, W78C154* or W78C58.
PSEN
TYPE
Advanced
Standard
MODE
Normal
Emulation
Normal
Emulation
DESCRIPTION
Functions same as in W78C438.
In high impedance state.
Pins ROMS1 and ROMS0 determine the function of PSEN. For
details, see Table D1 below.
In high impedance state.
ROMS1
0
0
1
1
ALE
TYPE
Advanced
Standard
ROMS0
0
1
0
1
FUNCTION of PSEN, PORT 0, AND PORT 2
Same as in the W78C51 (verify 4K ROM).
Same as in the W78C52 (verify 8K ROM).
Same as in the W78C154* (verify 16K ROM).
Same as in the W78C58 (verify 32K ROM).
Table D1.
MODE
Normal
Emulation
Normal
Emulation
DESCRIPTION
Functions same as in W78C32.
In high impedance state.
Functions same as in W78C52.
In high impedance state.
-4-