W78958B Datasheet, PDF (16/28 Pages) Winbond – 8-BIT EMULATION MICROCONTROLLER

W78958B
It is important that the W78958B not enter emulation mode after entering power-down mode, even if
the ICESET pin goes high. If the breakpoint address is the instruction that immediately follows
activation of the idle mode, the EMU pin will go high after the execution of the interrupt service
routine while the W78958B is being awakened from interrupt.
New Special Function Registers
NAME
HB
EPMA
PCL
PCH
MP2
P8
ADDR
OBJECT
A1 During the execution of "MOVX
@Ri," the content of HB is output to
AP6.
A2 EPMA.7 determines functions of
AP7.
EPMA.3−EPMA.0 determine values
of AP7<3:0> when EPMA.7 is "0."
A3 Accessed by ICE makers.
A4 Accessed by ICE makers.
A5 The bits of MP2 determine functions
of P2<7:0> during the emulation
mode for standard type.
A6 The content of P8 is output to port 8.
VALUE
AFTER
RESET
00H
TIME TO
ACCESS
NOTES
Both modes for
1
advanced type
70H
Both modes for
1
advanced type
00H Emu. mode for
both types
00H Emu. mode for
both types
0FFH Emu. mode for
2
(for POR ^{Ver. type}
only)
0FFH Both modes for
1
advanced type
XICON
C0 The bits of XICON determine/show
the functions/status of INT 2 −3.
00H
Both modes for
1
advanced type
Notes:
1. The instructions used to access these nonstandard registers may cause assembling errors with respect to the 2500 A. D.
assembler, but these errors can be ignored by adding directive ".RAMCHK OFF" ahead these instructions.
2. In standard type, the contents of MP2 must be set up correctly before the external ROM/RAM is accessed.
Power Reduction Function
The W78958B supports power reduction but is not guaranteed to duplicate the current specifications
of the W78C32.
The status of the external pins during the idle and power-down modes for the W78958B is shown in
the following tables.
Advanced Type:
MODE ^PIN
Idle
Power-down
ALE PSEN
11
00
PT0−PT3, P8
Port Data
Port Data
DP4
Floating
Floating
AP5 AP6
AP7
Address
@1
Address
@1
Note: Either 0 or decoded value by AP6<7:6>, depending the value of EPMA.7.
- 16 -