MPC555
/
MPC556
SIGNAL DESCRIPTIONS
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
2-21
VDDSYN –
This is the power supply of the PLL circuitry.
2.3.1.42 VSSSYN
Pin Name
: vsssyn
VSSSYN –
This is the power supply of the PLL circuitry.
2.3.1.43 ENGCLK/BUCLK
Pin Name
: engclk_buclk
ENGCLK –
This is the engineering clock output. Drive strength can be configured to
full strength, half strength or disabled. The drive strength is configured using the EE-
CLK[0:1] bits in the SCCR register in the SIU.
BUCLK –
When the chip is in limp mode, it is operating from a less precise on-chip
ring oscillator to allow the system to continue minimum functionality until the system
clock is fixed. This backup clock can be seen externally based on the values of the EE-
CLK[0:1] bits in the SCCR register in the USIU.
2.3.2 QSMCM PADS
2.3.2.1 PCS[0]/SS/QGPIO[0]
Pin Name
: pcs0_ss_b_qgpio0
PCS[0] –
This signal provides QSPI peripheral chip select 0.
SS –
Assertion of this bi-directional signal places the QSPI in slave mode.
QSPI GPIO[0] –
When this pin is not needed for a QSPI application it can be config-
ured as a general purpose input/output.
2.3.2.2 PCS[1:3]/QGPIO[1:3]
Pin Name
: pcs1_qgpio1 - pcs3_qgpio3 (3 pins)
PCS[1:3] –
These signals provide three QSPI peripheral chip selects.
QGPIO[1:3] –
When these pins are not needed for QSPI applications they can be con-
figured as a general purpose input/output.
2.3.2.3 MISO/QGPIO[4]
Pin Name
: miso_qgpio4
Master-In Slave-Out (MISO) –
This bi-directional signal furnishes serial data input to
the QSPI in master mode, and serial data output from the QSPI in slave mode.
QGPIO[4] –
When this pin is not needed for a QSPI application it can be configured
as a general purpose input/output.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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