MCF51EM256CLL Freescale Semiconductor, MCF51EM256CLL Datasheet - Page 307

• Manufacturer Part Number: MCF51EM256CLL
• Description: IC MCU 32BIT 256KB FLASH 100LQFP
• Manufacturer: Freescale Semiconductor
• Series: MCF51EMr

Specifications of MCF51EM256CLL

• Core Processor: Coldfire V1
• Core Size: 32-Bit
• Speed: 50MHz
• Connectivity: I²C, SCI, SPI
• Peripherals: LCD, LVD, PWM, WDT
• Number Of I /o: 63
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Data Converters: A/D 16x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-LQFP
• Processor Series: MCF51EM
• Core: ColdFire V1
• Data Bus Width: 32 bit
• Data Ram Size: 16 KB
• Interface Type: RS-232, LIN
• Maximum Clock Frequency: 50 MHz
• Number Of Timers: 3
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JLINK-CF-BDM26, EWCF
• Development Tools By Supplier: DEMOEM
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

13.4.5
The SPI can support data lengths of 8 or 16 bits. The length can be configured with the SPIMODE bit in
the SPIxC2 register.
In 8-bit mode (SPIMODE = 0), the SPI Data Register is comprised of one byte: SPIxDL. The SPI Match
Register is also comprised of only one byte: SPIxML. Reads of SPIxDH and SPIxMH will return zero.
Writes to SPIxDH and SPIxMH will be ignored.
In 16-bit mode (SPIMODE = 1), the SPI Data Register is comprised of two bytes: SPIxDH and SPIxDL.
Reading either byte (SPIxDH or SPIxDL) latches the contents of both bytes into a buffer where they
remain latched until the other byte is read. Writing to either byte (SPIxDH or SPIxDL) latches the value
into a buffer. When both bytes have been written, they are transferred as a coherent 16-bit value into the
transmit data buffer.
In 16-bit mode, the SPI Match Register is also comprised of two bytes: SPIxMH and SPIxML. Reading
either byte (SPIxMH or SPIxML) latches the contents of both bytes into a buffer where they remain latched
until the other byte is read. Writing to either byte (SPIxMH or SPIxML) latches the value into a buffer.
When both bytes have been written, they are transferred as a coherent 16-bit value into the transmit data
buffer.
Any switching between 8- and 16-bit data transmission length (controlled by SPIMODE bit) in master
mode will abort a transmission in progress, force the SPI system into idle state, and reset all status bits in
the SPIxS register. To initiate a transfer after writing to SPIMODE, the SPIxS register must be read with
SPTEF = 1, and data must be written to SPIxDH:SPIxDL in 16-bit mode (SPIMODE = 1) or SPIxDL in
8-bit mode (SPIMODE = 0).
In slave mode, user software should write to SPIMODE only once to prevent corrupting a transmission in
progress.
13.4.6
To accommodate a wide variety of synchronous serial peripherals from different manufacturers, the SPI
system has a clock polarity (CPOL) bit and a clock phase (CPHA) control bit to select one of four clock
formats for data transfers. CPOL selectively inserts an inverter in series with the clock. CPHA chooses
between two different clock phase relationships between the clock and data.
Figure 13-16
figure, the eight bit times are shown for reference with bit 1 starting at the first SPSCK edge and bit 8
ending one-half SPSCK cycle after the sixteenth SPSCK edge. The MSB first and LSB first lines show the
order of SPI data bits depending on the setting in LSBFE. Both variations of SPSCK polarity are shown,
but only one of these waveforms applies for a specific transfer, depending on the value in CPOL. The
SAMPLE IN waveform applies to the MOSI input of a slave or the MISO input of a master. The MOSI
waveform applies to the MOSI output pin from a master and the MISO waveform applies to the MISO
output from a slave. The SS OUT waveform applies to the slave select output from a master (provided
Freescale Semiconductor
Data Transmission Length
SPI Clock Formats
shows the clock formats when SPIMODE = 0 (8-bit mode) and CPHA = 1. At the top of the
Data can be lost if the data length is not the same for both master and slave
devices.
MCF51EM256 Series ColdFire Integrated Microcontroller Reference Manual, Rev. 8
NOTE
16-Bit Serial Peripheral Interface (SPI16)
13-21