Specifications

BASIC Stamp II
Parallax, Inc. • BASIC Stamp Programming Manual 1.8 • Page 207
2
BS2 Hardware
Figure H-1 is a schematic diagram of the BASIC Stamp II (BS2). In this
section we’ll describe each of the major components and explain its
function in the circuit.
Figure H-1
+
Input/Output Pins
Output: source 20mA each
sink 25mA each
Input: leakage < 1µA
threshold 1.4V
Schematic Diagram of the BASIC Stamp II (BS2-IC revA)
1. This diagram depicts the DIP/SOIC version of the PBASIC2 interpreter chip, since users
wishing to construct a BS2 from discrete components are most likely to use those parts.
Contact Parallax for a schematic depicting the SSOP (ultra-small surface mount) package
used in the BS2-IC module.
2. Numbers in parentheses—(#)—are pin numbers on the BS2-IC module. The BS2-IC has
the form factor of a 24-pin, 0.6" DIP.
3. Q1, Q2 and Q3 are Rohm part numbers. Other components may be substituted in custom
circuits, subject to appropriate design. Contact Parallax for design assistance.
4. U3 and U4 are Seiko part numbers. Other components may be substituted in custom
circuits, subject to appropriate design. Contact Parallax for design assistance.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RTCC MCLR
Vdd OSC1
NC OSC2
Vss RC7
NC RC6
RA0 RC5
RA1 RC4
RA2 RC3
RA3 RC2
RB0 RC1
RB1 RC0
RB2 RB7
RB3 RB6
RB4 RB5
PBASIC2 Interpreter Chip
(Parallax Custom PIC16C57)
1
2
3
4
NC
NC
NC
Vss
8
7
6
5
VDD
WP
SCL
SDA
24LC16B
+5V
4.7k
+5V
+5V
4.7k
10k
10k
4.7k
10k
+5V
10k
1/2 UMH11TN
DTA114EETL
S IN
(2)
S OUT
(1)
+5V
4.7k
10k
10k
1/2 UMH11TN
A TN
(3)
R ES
(22)
OUT
Vss
Vdd
+5V
V IN
(24)
Vss
+5V
V DD
(21)
*V SS
(23, 4)
22µF
10V
Power source for all
BS2 components
20-MHz
Ceramic
Resonator
4V Reset5V Reg.
P0
(5)
P1
(6)
P2
(7)
P3
(8)
P4
(9)
P5
(10)
P6
(11)
P7
(12)
P8
(13)
P9
(14)
P10
(15)
P11
(16)
P12
(17)
P13
(18)
P14
(19)
P15
(20)
2kB EEPROM
PBASIC2
N OTES
*Also called “ground”
throughout this
document.
S-8054HNS-81350HG
U4 U3
U1
U2
Q1
Q2
Q3
CSTCS
20.00
Schematic Diagram of the BASIC Stamp II (BS2-IC rev. A)