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Copyright © Matrix Multimedia Ltd.
Bus connections
1. Expansion bus
The pin connections on the expansion bus exactly mirror
the pin numbering on the 40-pin DIL socket. Note that
the pin numbering on the IDC socket is slightly different
to that on a DIL socket which results in the seemingly
odd arrangement of pins on the IDC chart.
PICmicro pinout
Bus name
18 Pin
8 Pin
14 Pin
20 Pin
28 Pin
40 Pin
Vpp/MCLR 4
4
4
4
1
1
Vdd
14
1
1
1
20
11 & 32
Vss
5
8
77
20
8 & 19
12 &31
OCS1
16
2
2
2
9
13
OCS2
15
3
3
3
10
14
RA0/AN0
17
19
2
2
RA1/AN1
18
18
3
3
RA2/AN2
1
4
4
RA3/AN3
2
4
5
5
RA4
3
3
6
6
RA5/AN4
4
2
7
7
RB0
6
21
33
RB1
7
22
34
RB2
8
5*
11*
23
35
RB3
9
24
36
RB4
10
13
25
37
RB5
11
12
26
38
RB6
12
6*
12*
11
27
39
RB7
13
7*
13*
10
28
40
RC0
10
16
11
15
RC1
9
15
12
16
RC2
8
14
13
17
RC3
7
7
14
18
RC4
6
6
15
23
RC5
5
5
16
24
RC6
8
17
25
RC7
9
18
26
RD0
19
RD1
20
RD2
21
RD3
22
RD4
27
RD5
28
RD6
29
RD7
30
RE0/AN5
8
RE1/AN6
9
RE2/AN7
10
For the 18, 28 and 40 pin devices the buses on devices
are largely upwards compatible - pin connections on an
18-pin device appear on a 28-pin device and a 40-pin
device, and pins on a 28-pin device appear on a 40-pin
device. This allows the 18, 28 and 40 pin DIL sockets to
be connected in parallel with the PICmicro bus structure
intact.
* This parallel connection is not possible with 8, 14 and
20 pin devices due to programming requirements which
means that there are anomalies with the pin connections
for the 8, 14 and 20 pin devices as follows:
Multiprogrammer port
line
Connection pin on 20
pin device
20 pin port line
RB2
5
RA2
RB6
6
RA1
RB7
7
RA0
Multiprogrammer port
line
Connection pin on 14
pin device
14 pin port line
RB2
5
RA2
RB6
6
RA1
RB7
7
RA0
Multiprogrammer port
line
Connection pin on 8
pin device
8 pin port line
RB2
1
RA2
RB6
12
RA1
RB7
13
RA0