COM20051 Datasheet, PDF (71/82 Pages) List of Unclassifed Manufacturers – Integrated Microcontroller and ARCNET (ANSI 878.1) Interface

USING THE COM20051'S EMULATION MODE
The COM20051 is unique among special
purpose 8051 based devices in that it can be
used in conjunction with a standard 16MHz
80C32 ICE. The COM20051 incorporates an
Emulate mode that puts the internal
microcontroller in a high impedance state so
an external processor (like an ICE) can access
the internal ARCNET core through the
COM20051's pins. The ICE should be connected
in parallel to the COM20051 as shown in Figure
24. The ICE should operate off of its internal
oscillator.
C2
33pf
C3
33pf
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Y1
16Mhz
EMULATOR POD
U3
31 _EA/VP
19 _X1
18
X2
9 _RESET
12
13
14
15
INT0
INT1
T0
T1
1
2
3
4
5
P1.0/T2
P1.1/T2x
P1.2
P1.3
6
7
8
P1.4
P1.5
P1.6
P1.7
8032
P0.0
39
38
P0.1
P0.2
P0.3
P0.4
37
36
35
34
P0.5
P0.6
P0.7
33
32
P2.0
21
22
P2.1
P2.2
P2.3
P2.4
23
24
25
26
P2.5
P2.6
27
28
P2.7
RD
WR
17
16
29
PSEN
ALE/P
TXD
RXD
30
11
10
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
A8
A9
A10
A11
A12
A13
A14
A15
C23 33pf
Y3
R19
1.5K
C22
33pf
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
SMSC COM20051
U1
35 _EA/VP
21 _X1
20 _X2
10
RESET
14
15
INT0
16
17
INT1
T0
T1
2
3
4
5
P1.0
P1.1
P1.2
6
7
P1.3
P1.4
8
9
P1.5
P1.6
P1.7
P0.0
P0.1
P0.2
43
42
41
40
AD0
AD1
AD2
AD3
P0.3 ₃₉
AD4
P0.4
P0.5
P0.6
P0.7
38
37
36
AD5
AD6
AD7
P2.0
24
25
P2.1
P2.2
26
27
P2.3
P2.4
P2.5
P2.6
P2.7
28
29
30
31
RD
19
18
WR
PSEN
32
33
ALE/P
TXD
13
11
RXD
PULSE1
PULSE2
RXIN
12
23
1
34
TXEN
COM20051
A8
A9
A10
A11
A12
A13
A14
A15
C0
C1
C2
C3
C4
C5
FIGURE 23 – CONNECTIONS FOR EMULATION MODE
71