MCF51EM256CLL Freescale Semiconductor, MCF51EM256CLL Datasheet - Page 392

• 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

Independent Robust Real Time Clock (IRTC)
This register stores the value of the month and year counters. The year bits do not store the year value but
calculate the increment in years. This is a signed value and the range of values is from –128 to +127. The
software programs the offset from that base year into this register. The BASE YEAR has been hard coded
in the design as the year 2112. For example, if the current year is 2007, then this will be represented in this
register as –105 or 0x97. The actual year value can be found by adding the BASE YEAR and the offset in
the IRTC_YEARMON[15:8] register. Hence the range of year supported will be 1984 (2112 – 128) to
2239 (2112 + 127). Hence for year calculation we have:
Actual year = Base year (i.e. 2112) + Offset year
The month register stores the count value of the months register. Writing to this register loads the months
counter with this new value. The valid values are mentioned in table above. Writing any other value will
not guarantee correct operation of IRTC. Both month and year are unaffected on software reset.
In BCD mode, the value of months counter is represented in BCD format and the bits used are shown in
the table above. Since the year value is a 2’s complement value this is not converted to BCD but the value
remains in binary even in BCD mode.
MCU should first read the INVAL bit of the IRTC_STATUS (bit 0) to determine that the counters are stable
and they can be changed. The INVAL bit ensures that no operation is done at the boundary of a second
when counters change value. MCU should check the status of this bit both during reads and writes.
17-8
MONTH
YEAR
Field
15–8
3–0
7:4
Year count value. Indicates the offset in years from the base year (hard coded as 2112) and does not show the
actual year value. This is a signed value.
Valid Values: –128 to 127 (Base year 2112 and if the value of YEAR bits is 0x10, the actual year will be 2112
+ 16 = 2128).
Reserved bits in binary mode. Read returns zeros. In BCD mode, these are used.
Month Count Value. Valid Values: 1 – 12
‘1’ – January
‘2’ – February
‘3’ – March
‘4’ – April
‘5’ – May
‘6’ – June
MCF51EM256 Series ColdFire Integrated Microcontroller Reference Manual, Rev. 8
Table 17-2. IRTC_YEARMON Field Descriptions
‘10’ – October
‘11’ – November
‘9’ – September
‘8’ – August
‘7’ – July
‘12’ – December
Description
‘0’ & ‘13’ to ‘15’ – Reserved. Should not
be used.
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