MCF51EM256CLL Freescale Semiconductor, MCF51EM256CLL Datasheet - Page 258

• 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

Internal Clock Source (ICS)
11.1.6
As noted, this module is essentially a glorified multiplexor coupled with a simple test for comparing the
relative health of 3-possible on-chip clock sources. The self-test feature allows all three counters to clock
for exactly the same amount of time. Any of the three counters hitting the maximum value of 0xFF
terminates the test. Software can then compare the three registers to obtain a crude (~1.2%) measure of
how well the three frequencies correlate.
This self test can be run at any time.
11-4
CNTIR
Field
7-0
Operation
CNTIR - This register is one of three used to compare XOSC1, XOSC2 and internal relaxation oscillator
frequencies. It is initialized to zero upon a write of “1” to CSSCTRL[TEST]. It contains a valid value once
CSSCTRL[TEST] resets itself to “0”. By comparing the values of the three registers, application code can
determine the crude health of the various clock sources.
MCF51EM256 Series ColdFire Integrated Microcontroller Reference Manual, Rev. 8
Table 11-5. CSSTMRIR Register Field Descriptions
Description
Freescale Semiconductor