DSPIC30F5011-20I/PTG Microchip Technology, DSPIC30F5011-20I/PTG Datasheet - Page 21

• Manufacturer Part Number: DSPIC30F5011-20I/PTG
• Description: IC, DSC, 16BIT, 66KB, 40MHZ 5.5V TQFP-64
• Manufacturer: Microchip Technology
• Series: DsPIC30Fr

Specifications of DSPIC30F5011-20I/PTG

• Core Frequency: 40MHz
• Core Supply Voltage: 5.5V
• Embedded Interface Type: CAN, I2C, SPI, UART
• No. Of I/o's: 52
• Flash Memory Size: 66KB
• Supply Voltage Range: 2.5V To 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2.4.1
The 17 x 17-bit multiplier is capable of signed or
unsigned operation and can multiplex its output using a
scaler to support either 1.31 fractional (Q31) or 32-bit
integer results. Unsigned operands are zero-extended
into the 17th bit of the multiplier input value. Signed
operands are sign-extended into the 17th bit of the
multiplier input value. The output of the 17 x 17-bit
multiplier/scaler
sign-extended to 40 bits. Integer data is inherently
represented as a signed two’s complement value,
where the MSB is defined as a sign bit. Generally
speaking, the range of an N-bit two’s complement
integer is -2
range is -32768 (0x8000) to 32767 (0x7FFF) including
‘0’. For a 32-bit integer, the data range is
-2,147,483,648
(0x7FFF FFFF).
When the multiplier is configured for fractional
multiplication, the data is represented as a two’s com-
plement fraction, where the MSB is defined as a sign bit
and the radix point is implied to lie just after the sign bit
(QX format). The range of an N-bit two’s complement
fraction with this implied radix point is -1.0 to (1 – 2
For a 16-bit fraction, the Q15 data range is -1.0
(0x8000) to 0.999969482 (0x7FFF) including ‘0’ and
has a precision of 3.01518x10
the 16x16 multiply operation generates a 1.31 product
which has a precision of 4.65661 x 10
The same multiplier is used to support the MCU multi-
ply instructions which include integer 16-bit signed,
unsigned and mixed sign multiplies.
The MUL instruction may be directed to use byte or
word sized operands. Byte operands will direct a 16-bit
result, and word operands will direct a 32-bit result to
the specified register(s) in the W array.
2.4.2
The
adder/subtracter with automatic sign extension logic. It
can select one of two accumulators (A or B) as its
pre-accumulation source and post-accumulation desti-
nation. For the ADD and LAC instructions, the data to be
accumulated or loaded can be optionally scaled via the
barrel shifter, prior to accumulation.
© 2008 Microchip Technology Inc.
data
N-1
MULTIPLIER
DATA ACCUMULATORS AND
ADDER/SUBTRACTER
accumulator
to 2
(0x8000 0000)
is
N-1
- 1. For a 16-bit integer, the data
a
33-bit
consists
-5
. In Fractional mode,
to
value
-10
2,147,483,645
of
.
which
a
40-bit
1-N
is
).
2.4.2.1
The adder/subtracter is a 40-bit adder with an optional
zero input into one side and either true, or complement
data into the other input. In the case of addition, the
carry/borrow input is active high and the other input is
true data (not complemented), whereas in the case of
subtraction, the carry/borrow input is active low and the
other input is complemented. The adder/subtracter
generates overflow status bits SA/SB and OA/OB,
which are latched and reflected in the STATUS
register:
• Overflow from bit 39: this is a catastrophic
• Overflow into guard bits 32 through 39: this is a
The adder has an additional saturation block which
controls accumulator data saturation, if selected. It
uses the result of the adder, the overflow status bits
described above, and the SATA/B (CORCON<7:6>)
and ACCSAT (CORCON<4>) mode control bits to
determine when and to what value to saturate.
Six STATUS register bits have been provided to
support saturation and overflow; they are:
1.
2.
3.
4.
5.
6.
The OA and OB bits are modified each time data
passes through the adder/subtracter. When set, they
indicate that the most recent operation has overflowed
into the accumulator guard bits (bits 32 through 39).
The OA and OB bits can also optionally generate an
arithmetic warning trap when set and the correspond-
ing overflow trap flag enable bit (OVATE, OVBTE) in
the INTCON1 register (refer to Section 4.0 “Inter-
rupts”) is set. This allows the user to take immediate
action, for example, to correct system gain.
overflow in which the sign of the accumulator is
destroyed.
recoverable overflow. This bit is set whenever all
the guard bits are not identical to each other.
dsPIC30F5011/5013
OA:
AccA overflowed into guard bits
OB:
AccB overflowed into guard bits
SA:
AccA saturated (bit 31 overflow and saturation)
or
AccA overflowed into guard bits and saturated
(bit 39 overflow and saturation)
SB:
AccB saturated (bit 31 overflow and saturation)
or
AccB overflowed into guard bits and saturated
(bit 39 overflow and saturation)
OAB:
Logical OR of OA and OB
SAB:
Logical OR of SA and SB
Adder/Subtracter, Overflow and
Saturation
DS70116H-page 21