XC2200 Derivatives
System Units (Vol. 1 of 2)
System Control Unit (SCU)
User’s Manual
6-178
V2.1, 2008-08
SCU, V1.13
6.8.8
ERU Registers
6.8.8.1
External Input Selection Register EXISEL
This register selects the A and B inputs for all four ERS units. The possible input signals
are given in
.
EXISEL
External Input Select Register ESFR (F1A0
H
/D0
H
)
Reset Value: 0000
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXS3B
EXS3A
EXS2B
EXS2A
EXS1B
EXS1A
EXS0B
EXS0A
rw
rw
rw
rw
rw
rw
rw
rw
Field
Bits
Type Description
EXS0A
[1:0]
rw
External Source Select for A0 (ERS0)
This bit field defines which input is selected for A0.
00
B
Input ERU_0A0 is selected
01
B
Input ERU_0A1 is selected
10
B
Input ERU_0A2 is selected
11
B
Input ERU_0A3 is selected
EXS0B
[3:2]
rw
External Source Select for B0 (ERS0)
This bit field defines which input is selected for B0.
00
B
Input ERU_0B0 is selected
01
B
Input ERU_0B1 is selected
10
B
Input ERU_0B2 is selected
11
B
Input ERU_0B3 is selected
EXS1A
[5:4]
rw
External Source Select for A1 (ERS1)
This bit field defines which input is selected for A1.
00
B
Input ERU_1A0 is selected
01
B
Input ERU_1A1 is selected
10
B
Input ERU_1A2 is selected
11
B
Input ERU_1A3 is selected
EXS1B
[7:6]
rw
External Source Select for B1 (ERS1)
This bit field defines which input is selected for B1.
00
B
Input ERU_1B0 is selected
01
B
Input ERU_1B1 is selected
10
B
Input ERU_1B2 is selected
11
B
Input ERU_1B3 is selected