1 2 3 4
Buffer/Line Driver
VCC
D1
D D
R16 100
TCK
1N4148 R17 100
R26 R25 R24 R23 R22 R21
AF
4.7k 4.7k 4.7k 4.7k 4.7k 4.7k
R18 100
TDI
U1
2 18 R19 100
STROBE 1A1 1Y1
4 16
AUTO 1A2 1Y2 INI
6 14
D0 1A3 1Y3
8 12 R20 100
INIT 1A4 1Y4
11 9
SEL_IN 2A1 2Y1 TMS
13 7
TDO 2A2 2Y2
15 5
D7 2A3 2Y3
17 3 VCC
2A4 2Y4 nACK
1 20
1G VCC
19 10
2G GND
C C
BUSY
C1
74VHC244
20-SOIC
0.1uF
GND
GND
VCC
JP1
TCK 1 2
TDO 3 4
TMS 5 6 INI
B B
7 8 AF
TDI 9 10
HEADER 5X2
R1
330ohm
GND
L1
LED
10 Pin Header to ISP Board
GND
Title
A A
Size Number Revision
Orcad A
Date: 27-Sep-2001 Sheet of
File: C:\ISP\isp_cable\rev5\isp_r5.ddb Drawn By:
1 2 3 4
1 2 3 4
Parallel Port Section Voltage Detection
VCC
D D
R2 100
STROBE
R3 100
AUTO
R12 10K 1.36V at VCC = 3.3 R13 4.7K
P1
R4 100 2.06V at VCC = 5.0
1
D0
1.5V - 1.6V Vref
14
2
15
ERROR
3
100
R5
16 D2 1N4148
INIT
4
17
SEL_IN
5
R6 100
18 VCC
6 R14 3.3K
D3 1N4148
19
C C
7
20 R7 100
8
D7
D4
21 1N4148 VCC
9 R8 100
22
nACK
10 4 8 4 8
23 R9 100
11 LM393 U2A LM393 U2B
BUSY
8-SOP 8-SOP
24
12 VCC GND R15 30K
25 R10 4.7K
13
R11 4.7K
ERROR
DB25
3V = 0 GND
5V = 1
B B
GND
Title
A A
Size Number Revision
Orcad A
Date: 10-Jun-2002 Sheet of
File: C:\ISP\isp_cable\rev5\isp_r5.ddb Drawn By:
1 2 3 4
-
+
-
+
2
3
6
5
1
7