Datasheet
revolution
Revolution Education Ltd. Email: info@rev-ed.co.uk Web: www.rev-ed.co.uk Version 2.0 01/09/2002
28-PINPROJ.P65
2
28-PIN PROJECT BOARD
Digital Outputs
Each digital output is connected to a transistor as shown below.
ULN2803A
M
MICRO-
CONTROLLER
V1+ (6V)
0V
V2+ (6-12V)
0V
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
both 0V lines must be connected
separate supply
M
MICRO-
CONTROLLER
6V
0V
28-Pin Project Board Circuit
On the board the transistors are contained in a single ULN2803A darlington driver IC.
The equivalent output circuit is shown below.
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
4 MHz
4k7
V1+
0V
Optional
reset
switch
ULN2803A
analogue a
analogue b
analogue c
analogue d
(serial input-PICAXE only)
(serial output-PICAXE only)
V2+
in 0
in 1
in 2
in 3
in 4
in 5
in 6
in 7
out 7
out 6
out 5
out 4
out 3
out 2
out 1
out 0
all 10k
jumper link added
when using single
power supply (V1+)
0V