XC2200 Derivatives
System Units (Vol. 1 of 2)
The External Bus Controller EBC
User’s Manual
9-16
V2.1, 2008-08
EBC_X8, V1.0d1
9.3.3
The EBC Mode Register 1
EBC MODe register 1
controls the general use of port pins for external bus.
Notes
1. Disabled bus pins may be used for general purpose IO or for alternate functions (see
port and pin descriptions).
2. After reset, the address and data bus pins are enabled, but in Idle state.
EBCMOD1
EBC Mode Register 1
XSFR (EE02
H
/--)
Reset Value: 003F
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
WRP
DIS
DHP
DIS
ALP
DIS
A0P
DIS
APDIS
-
-
-
-
-
-
-
-
rw
rw
rw
rw
rw
Field
Bits
Type
Description
WRPDIS
7
rw
WR/WRL Pin Disable
0
B
WR/WRL pin enabled
1
B
WR/WRL pin disabled
DHPDIS
6
rw
Data High Port Pins Disable
0
B
Address/Data bus pins 15-8 enabled
1
B
Address/Data bus pins 15-8 disabled
ALPDIS
5
rw
Address Low Pins Disable
0
B
Address bus pins 7-0 generally enabled
(depending on APDIS/A0PDIS)
1
B
Address bus pins 7-0 disabled
A0PDIS
4
rw
Address Bit 0 Pin Disable
0
B
Address bus pin 0 enabled
1
B
Address bus pin 0 disabled
APDIS
[3:0]
rw
Address Port Pins Disable
0000
B
Address bus pins 15-1 enabled
0001
B
Pin A15 disabled, A14-A1 enabled
0010
B
Pins A15-A14 disabled, A13-A1 enabled
0011
B
Pins A15-A13 disabled, A12-A1 enabled
…
…
1110
B
Pins A15-A2 disabled, A1 enabled
1111
B
Address bus pins 15-1 disabled