W78958B Datasheet, PDF (12/28 Pages) Winbond – 8-BIT EMULATION MICROCONTROLLER

W78958B
FUNCTIONAL DESCRIPTION
The W78958B is available in two types, an advanced type and a standard type, which are intended
for use with different end products. The default product type is the advanced type. Both the advanced
type and the standard type are also available with an emulation function. To configure the W78958B
to operate as the advanced type or standard type and to enter the emulation mode, adjust the input
pin settings as shown in the table below. (Note that a transition between the advanced type and
standard type is not permitted after power-on.)
ENSTD
I
EA
I
ICESET
I
EMU
O
Advanced → Emulation
High
Low
Low
High
Low
High
Standard → Emulation
Low
High/Low
Low
High
Low
High
Notes
1
2
Notes:
1. This pin is pulled high internally.
2. This pin is pulled low internally.
The type transition diagram for the advanced and standard types is shown below:
POWER ON
ENSTD =1
EA = 0
ENSTD =1
ADVANCED
TYPE
ICESET = 1
ICESET = 0
STANDARD
TYPE
ICESET = 1
ICESET = 0
EMULATION
EMULATION
Figure E. 1
Note that a transition between the advanced type and standard type is not permitted after power-on.
Advanced Type, Normal Mode
At power-on, if ENSTD is set to high or left floating and EA is set to low, then the W78958B will
operate as the advanced type. The advanced type provides four general-purpose I/O ports for
W78C32 applications; the address and data bus are separated from Port 0 and Port 2 so that these
ports can be used as general-purpose I/O ports. In this type, DP4 is the data bus for external program
and data memory, AP5<7:0> are the low byte address, AP6<7:0> are the high byte address, PSEN
enables the external program memory to DP4, and P3.6 ( WR ) and P3.7(RD ) are the write and read
control signals for the external data memory, respectively. The external latch for multiplexing the low
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