MC68HC16Z1CFC16 Freescale Semiconductor, MC68HC16Z1CFC16 Datasheet - Page 229

• Manufacturer Part Number: MC68HC16Z1CFC16
• Description: IC MPU 1K RAM 16MHZ 132-PQFP
• Manufacturer: Freescale Semiconductor
• Series: HC16r

Specifications of MC68HC16Z1CFC16

• Core Processor: CPU16
• Core Size: 16-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Type: ROMless
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 132-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -

9.3.5.2 Master Wrap-Around Mode
M68HC16 Z SERIES
USER’S MANUAL
QSPI operation is initiated by setting the SPE bit in SPCR1. Shortly after SPE is set,
the QSPI executes the command at the command RAM address pointed to by
NEWQP. Data at the pointer address in transmit RAM is loaded into the data serializer
and transmitted. Data that is simultaneously received is stored at the pointer address
in receive RAM.
When the proper number of bits have been transferred, the QSPI stores the working
queue pointer value in CPTQP, increments the working queue pointer, and loads the
next data for transfer from transmit RAM. The command pointed to by the incremented
working queue pointer is executed next, unless a new value has been written to
NEWQP. If a new queue pointer value is written while a transfer is in progress, that
transfer is completed normally.
When the CONT bit in a command RAM byte is set, PCS pins are continuously driven
to specified states during and between transfers. If the chip-select pattern changes
during or between transfers, the original pattern is driven until execution of the follow-
ing transfer begins. When CONT is cleared, the data in register PORTQS is driven be-
tween transfers. The data in PORTQS must match the inactive states of SCK and any
peripheral chip-selects used.
When the QSPI reaches the end of the queue, it sets the SPIF flag. SPIF is set during
the final transfer before it is complete. If the SPIFIE bit in SPCR2 is set, an interrupt
request is generated when SPIF is asserted. At this point, the QSPI clears SPE and
stops unless wrap-around mode is enabled.
Wrap-around mode is enabled by setting the WREN bit in SPCR2. The queue can
wrap to pointer address $0 or to the address pointed to by NEWQP, depending on the
state of the WRTO bit in SPCR2.
In wrap-around mode, the QSPI cycles through the queue continuously, even while
the QSPI is requesting interrupt service. SPE is not cleared when the last command
in the queue is executed. New receive data overwrites previously received data in re-
ceive RAM. Each time the end of the queue is reached, the SPIF flag is set. SPIF is
not automatically reset. If interrupt-driven QSPI service is used, the service routine
must clear the SPIF bit to end the current interrupt request. Additional interrupt re-
quests during servicing can be prevented by clearing SPIFIE, but SPIFIE is buffered.
Clearing it does not end the current request.
Wrap-around mode is exited by clearing the WREN bit or by setting the HALT bit in
SPCR3. Exiting wrap-around mode by clearing SPE is not recommended, as clearing
SPE may abort a serial transfer in progress. The QSPI sets SPIF, clears SPE, and
stops the first time it reaches the end of the queue after WREN is cleared. After HALT
is set, the QSPI finishes the current transfer, then stops executing commands. After
the QSPI stops, SPE can be cleared.
Freescale Semiconductor, Inc.
For More Information On This Product,
QUEUED SERIAL MODULE
Go to: www.freescale.com
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