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14 mpc8540 real-time clock input, 15 mpc8540 lbc clock divisor, Mpc8540 real-time clock input – Artesyn MVME3100 Single Board Computer Installation and Use (June 2014) User Manual

Page 138: Mpc8540 lbc clock divisor, Programming details

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Programming Details

MVME3100 Single Board Computer Installation and Use (6806800M28E)

138

7.14 MPC8540 Real-Time Clock Input

The MPC8540 real-time clock (RTC) input is driven by a 1 MHz clock generated by the control
and timers PLD. This provides a fixed clock reference for the RTC that software can use as a
known timing reference. To select this 1 MHz clock as the RTC timer reference, software must
set the SEL_TBCLK bit in the MPC8540 HID0 register.

7.15 MPC8540 LBC Clock Divisor

The MPC8540 LBC clock output is used by the control and timers PLD. The LBC clock is derived
from a divide by 2, 4 or 8 ratio of the internal CCB (core complex bus) clock as determined by
the clock ratio register (LCRR[CLKDIV]). For proper operation of the local bus, CLKDIV must be
set for divide by 8, which is the default value. The software must leave this register configured
for divide by 8 during initialization.

MPC9855

CLK66

25

Oscillator

2

3.3V

BCM5461S

CLK25_25V_PHY

25

Oscillator/
Buffer

2

2.5V

BCM5221

CLK25_33V_PHY

25

Oscillator/
Buffer

1

3.3V

Control and Timers
PLD

CLK25_33V_PLD

25

Oscillator/
Buffer

1

3.3V

CLK_LBC

CCB_CLK/8 (333
MHz/8)

MPC8540

1

3.3V

QUART

CLK_UART

1.8432

Oscillator

1

3.3V

sATA

CLK25

25

Oscillator

1

3.3V

USB

CLK48

48

Oscillator

1

3.3V

RTC

CLK32

32.768 kHz

Crystal

1

3.3V

Table 7-10 Clock Assignments (continued)

Device

Clock Signal(s)

Frequency (MHz)

Clock Tree
Source

Qty

VIO