Specifications

HARDWARE PREPARATION AND INSTALLATION
2-6 MPC505EVBUM/D
2.2.2 Clock Source Select Header (J2)
Use jumper header J2 to select either a crystal or clock oscillator as the MCU clock source. The
drawing below shows the factory configuration: bus wire soldered on pins 2 and 3. This
configuration selects the crystal clock source; crystal in socket at located Y1. When you want to
use the clock oscillator as the EVB clock, move the bus wire on J2 from pins 2 and 3 to pins 1
and 2 and remove the bus wire on J1 (see paragraph 2.2.1). This disconnects the MCU XTAL pin
from the crystal clock circuit at location Y1 and selects the crystal oscillator (U7) as the MCU
clock source. The frequency of the crystal clock circuit is 4 MHz. The frequency of the crystal
oscillator circuit can be as fast as 40 MHz.
J2
321
Bus Wire
2.2.3 Keep Alive Power 2 Select Header (J3)
Jumper header J3 provides power to the MCU-internal RAM module via the MCU VKAPWR2
pin. You may use either the on-board +3.3 Vdc (jumper on J3 pins 1 and 2) or connect an
external +3.3 Vdc power supply to J3 pins 2 and 3. An external +3.3 Vdc power supply on J3
pins 2 and 3 will maintain MCU-internal RAM data after EVB power is turned OFF. To attach
an external power supply to VKAPWR2: remove the jumper on J3 pins 1 and 2, and connect the
power supply ground to J3 pin 3 and +3.3 Vdc to pin 2.
CAUTION
Applying power to the EVB with J4 removed and no external
power supply attached to J4 will damage the MPC505 MCU.
Always keep a jumper or an external +3.3 Vdc power supply on J4
pins 1 and 2. If using an external power supply, apply VKAPWR1
before powering up the EVB.
HARDWARE PREPARATION AND INSTALLATION
MPC505EVBUM/D 2-3
Table 2-1. Jumper Header Types
Jumper Header
Type Symbol Description
two-pin with solder
strap
Two-pin plate through holes (without jumper header block) and
designated as JX (X = the jumper header number). Bus wire
soldered between the two pins of the plate through holes to
create a short.
two-pin Two-pin jumper header and designated as JX (X = the jumper
header number). Use a fabricated jumper to create a short
between the two pins of the jumper header.
two-pin with jumper Two-pin jumper header with jumper, designated as JX (X = the
jumper header number).
three-pin Three-pin jumper header, designated as JX (X = the jumper
header number). Use a fabricated jumper to create a short
between two of the three pins of the jumper header.
three-pin with jumper Three-pin jumper header with jumper and designated as JX (X =
the jumper header number). To change the factory jumper header
configuration, move the jumper to the two desired pins.
Table 2-2. MPFB Jumper Header Descriptions
Jumper
Header Type Description
J1
Crystal clock
sourcr select
header
(XTAL)
2 1
Bus wire soldered between pins 1 and 2 (factory default); selects the EVB
on-board 4 MHz crystal clock source.
Bus wire between pins 1 and 2 is removed; lets you select an external
clock source as the MCU EXTAL input signal.
J2
Clock
oscillator
source select
header
(EXTAL)
3 2 1
Bus wire between pins 1 and 2; lets you select an crystal oscillator clock
source as the MCU EXTAL input signal. (You must remove the bus wire
between pins 1 and 2 on
Bus wire soldered between pins 2 and 3 (factory default); selects the EVB
on-board 4 MHz crystal clock source.
J3
Keep alive
power 2 select
header
3 2 1
Jumper installed on pins 1 and 2 (factory default); keep alive power 2 is
active as long as power is applied to the EVB (+3.3 Vdc present on the
VKAPWR2 pin of the MCU).
+3.3 Vdc external power supply attached to pins 2 and 3; maintains MCU-
internal RAM after EVB power is turned OFF.
Fr
eescale S
emiconduct
or
, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc...