MC68EC000EI10 Freescale Semiconductor, MC68EC000EI10 Datasheet - Page 35

• Manufacturer Part Number: MC68EC000EI10
• Description: IC MPU 32BIT 10MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68EC000EI10

• Processor Type: M680x0 32-Bit
• Speed: 10MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

Introduction
A packed decimal real data format with the SE and both Y bits set, an exponent of $FFF,
and a nonzero 16-bit decimal fraction is a NAN. When the FPU uses this format, the fraction
of the NAN is moved bit- by-bit into the extended-precision mantissa of a floating-point data
register. The exponent of the register is set to signify a NAN, and no conversion occurs. The
MSB of the most significant digit in the decimal fraction (the MSB of digit 15) is a don’t care,
as in extended-precision NANs, and the MSB of minus one of digit 15 is the SNAN bit. If the
NAN bit is a zero, then it is an SNAN.
If a non-decimal digit ($A – $F) appears in the exponent of a zero, the number is a true zero.
The FPU does not detect non-decimal digits in the exponent, integer, or fraction digits of an
in-range packed decimal real data format. These non-decimal digits are converted to binary
in the same manner as decimal digits; however, the result is probably useless although it is
repeatable. Since an in-range number cannot overflow or underflow when converted to
extended precision, conversion from the packed decimal real data format always produces
normalized extended-precision numbers.
1-24
Sign
Explicit Integer Bit
Biased Exponent Format Maximum
Mantissa
Representation of Fraction
Approximate Ranges
Maximum Positive Normalized
Minimum Positive Normalized
Minimum Positive Denormalized
Data Type
Nonsignaling
Signaling
Nonzero Bit Pattern Created by User
Fraction When Created by FPCP
+In-Range
–In-Range
+Zero
–Zero
Infinity
SNAN
NAN
Table 1-7. Packed Decimal Real Format Summary
M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL
SM
0/1
0/1
0/1
0
1
0
1
SE
0/1
0/1
0/1
0/1
1
1
1
Table 1-6. Extended-Precision Real
Format Summary (Continued)
Y
X
X
X
X
1
1
1
Y
X
X
1
1
1
X
X
Exponent
$000–$999
$000–$999
$000–$999
$000–$999
NANs
3-Digit
$FFF
$FFF
$FFF
$XXX0–$XXX9
$XXX0–$XXX9
Integer
1-Digit
$XXXX
$XXXX
$XXXX
$XXX0
$XXX0
1.11111…1111
32767 ($7FFF)
x.1xxxx…xxxx
x.0xxxx…xxxx
x.xxxxx…xxxx
1.7
1.2
3.7
Don’t Care
Don’t Care
Nonzero
10
10
10
–4932
4932
4951
16-Digit Fraction
$00…01–$99…99
$00…01–$99…99
$00…00
Nonzero
Nonzero
$00…00
$00…00
MOTOROLA