Freescale Semiconductor MPC5748G EVB, Руководство пользователя

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MPC5748G EVB User Guide, User Guide, Rev. 0, 08/2015
28 Freescale Semiconductor, Inc.
8.3. Hex Encoder Switch (SW2, J26, P20)
There is a single hex encoded 16 position rotary switch on the EVB. This outputs a binary encoded hex
value (active high) on 4 MCU ports (Port D[0..3]) as well as a 4 pin header P20. There is a jumper J26
which can be used to isolate the supply to the hex encoder if required. This prevents any voltage being
asserted on the MCU pins irrespective of the position of the switch
Table 21. Hex Encoder Switch (SW2)
Position
HEX_SW4
(PD3, P20-4)
HEX_SW3
(PD2, P20-3)
HEX_SW2
(PD1, P20-2)
HEX_SW1
(PD0, P20-1)
0
0 0 0 0
1
0 0 0
1
2
0 0
1
0
3 0 0 1 1
4
0
1
0 0
5 0 1 0 1
6 0 1 1 0
7 0 1 1 1
8 1
0 0 0
9 1 0 0 1
A
1
0 1 0
B
1 0 1 1
C
1
1 0 0
D
1 1 0 1
E
1 1 1 0
F
1 1 1 1
Table 22. Hex Encoder Switch Power Jumper (J26)
Jumper Position PCB Legend Description
J26
(3V3)
FITTED ( D )
The hex encoder switch is powered with 3.3V (functional)
Removed
The hex encoder switch is not powered and will not drive outputs
NOTE
The MCU ports used on the user pushbutton switches are also routed to
the GPIO matrix.
There are zero ohm resistors on the direct connections between the switch
output and the MCU pins. These can be removed if required to isolate the
switch from the respective MCU pin (useful if the switch is being
manually routed to another pin on the GPIO matrix).
The hex encoder
switch is located
above the user
pushbutton switches