Clock Source Select Header (P6); Clock Divider Header (P9) - Motorola M68EM05A24 User Manual

3.1.3

Clock Source Select Header (P6)

3.1.4

Clock Divider Header (P9)

FABRICATED
HC05A24EM USER'S MANUAL
Jumper header P6 determines the source of the clock signal. The dia-
gram below shows the factory configuration: the fabricated jumper
between pins 2 and 3 selects the A24EM canned oscillator clock source.
This is the only correct configuration for an A24EM that is part of an
HC05EVS.
FABRICATED
JUMPER
The P6 pins 1 and 2 configuration is not correct for an A24EM that is
part of an HC05EVS system.
Jumper header P9 determines which internal clock divider of the MCU
to use after power on or reset. The diagram below shows the factory con-
figuration: the fabricated jumper between pins 1 and 2 selects the divide
by two MCU clock divider. This is the correct configuration for a 4 MHz
clock source. If a 16 MHz clock source is used. The user must remove
the fabricated jumper between pins 1 and 2 to select the divide by eight
MCU clock divider.
INTERNAL
CLOCK DIVIDER
P9
JUMPER
P6
1
MMDS05
2
XTAL
3
NOTE
1
OPEN = OSC/8
CLOSE = OSC/2
2
3
MOTOROLA
3-3