DSPIC30F4011T-30I/PT Microchip Technology, DSPIC30F4011T-30I/PT Datasheet - Page 23

• Manufacturer Part Number: DSPIC30F4011T-30I/PT
• Description: IC,DSP,16-BIT,CMOS,TQFP,44PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: dsPIC™ 30Fr

Specifications of DSPIC30F4011T-30I/PT

• Rohs Compliant: YES
• Core Processor: dsPIC
• Core Size: 16-Bit
• Speed: 30 MIPs
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, Motor Control PWM, QEI, POR, PWM, WDT
• Number Of I /o: 30
• Program Memory Size: 48KB (16K x 24)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.5 V ~ 5.5 V
• Data Converters: A/D 9x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: AC30F006 - MODULE SKT FOR DSPIC30F 44TQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: DSPIC30F4011T30IP

The SA and SB bits are modified each time data passes
through the adder/subtracter but can only be cleared by
the user. When set, they indicate that the accumulator
has overflowed its maximum range (bit 31 for 32-bit
saturation or bit 39 for 40-bit saturation) and is saturated
(if saturation is enabled). When saturation is not
enabled, SA and SB default to bit 39 overflow and thus
indicate that a catastrophic overflow has occurred. If the
COVTE bit in the INTCON1 register is set, SA and SB
bits generate an arithmetic warning trap when saturation
is disabled.
The overflow and saturation Status bits can optionally
be viewed in the STATUS register (SR) as the logical
OR of OA and OB (in bit OAB) and the logical OR of SA
and SB (in bit SAB). This allows programmers to check
one bit in the STATUS register to determine if either
accumulator has overflowed, or one bit to determine if
either accumulator has saturated. This would be useful
for complex number arithmetic which typically uses
both the accumulators.
The device supports three Saturation and Overflow
modes:
1.
2.
3.
© 2010 Microchip Technology Inc.
Bit 39 Overflow and Saturation:
When bit 39 overflow and saturation occurs, the
saturation logic loads the maximally positive 9.31
(0x7FFFFFFFFF) or maximally negative 9.31
value
accumulator. The SA or SB bit is set and
remains set until cleared by the user. This is
referred to as ‘super saturation’ and provides
protection against erroneous data or unexpected
algorithm problems (e.g., gain calculations).
Bit 31 Overflow and Saturation:
When bit 31 overflow and saturation occurs, the
saturation logic then loads the maximally posi-
tive 1.31 value (0x007FFFFFFF) or maximally
negative 1.31 value (0x0080000000) into the
target accumulator. The SA or SB bit is set and
remains set until cleared by the user. When this
Saturation mode is in effect, the guard bits are not
used (so the OA, OB or OAB bits are never set).
Bit 39 Catastrophic Overflow
The bit 39 overflow Status bit from the adder is
used to set the SA or SB bit, which remain set
until cleared by the user. No saturation operation
is performed and the accumulator is allowed to
overflow (destroying its sign). If the COVTE bit in
the INTCON1 register is set, a catastrophic
overflow can initiate a trap exception.
(0x8000000000)
into
the
target
2.4.2.2
The MAC class of instructions (with the exception of
MPY, MPY.N, ED and EDAC) can optionally write a
rounded version of the high word (bits 31 through 16)
of the accumulator that is not targeted by the instruction
into data space memory. The write is performed across
the X bus into combined X and Y address space. The
following addressing modes are supported:
1.
2.
2.4.2.3
The round logic is a combinational block, which per-
forms a conventional (biased) or convergent (unbiased)
round function during an accumulator write (store). The
Round mode is determined by the state of the RND bit
in the CORCON register. It generates a 16-bit, 1.15 data
value which is passed to the data space write saturation
logic. If rounding is not indicated by the instruction, a
truncated 1.15 data value is stored and the least
significant word is simply discarded.
Conventional rounding takes bit 15 of the accumulator,
zero-extends it and adds it to the ACCxH word (bits 16
through 31 of the accumulator). If the ACCxL word (bits
0 through 15 of the accumulator) is between 0x8000
and 0xFFFF (0x8000 included), ACCxH is incre-
mented. If ACCxL is between 0x0000 and 0x7FFF,
ACCxH is left unchanged. A consequence of this algo-
rithm is that over a succession of random rounding
operations, the value tends to be biased slightly
positive.
Convergent (or unbiased) rounding operates in the
same manner as conventional rounding, except when
ACCxL equals 0x8000. If this is the case, the LSb
(bit 16 of the accumulator) of ACCxH is examined. If it
is ‘1’, ACCxH is incremented. If it is ‘0’, ACCxH is not
modified. Assuming that bit 16 is effectively random in
nature, this scheme removes any rounding bias that
may accumulate.
The SAC and SAC.R instructions store either a trun-
cated (SAC) or rounded (SAC.R) version of the contents
of the target accumulator to data memory, via the X bus
(subject to data saturation, see
Space Write
of instructions, the accumulator write-back operation
functions in the same manner, addressing combined
DSC (X and Y) data space though the X bus. For this
class of instructions, the data is always subject to
rounding.
dsPIC30F4011/4012
W13, Register Direct:
The rounded contents of the non-target
accumulator are written into W13 as a
1.15 fraction.
[W13]+ = 2, Register Indirect with Post-Increment:
The rounded contents of the non-target accumu-
lator are written into the address pointed to by
W13 as a 1.15 fraction. W13 is then
incremented by 2 (for a word write).
Saturation”). Note that for the MAC class
Accumulator ‘Write-Back’
Round Logic
Section 2.4.2.4 “Data
DS70135G-page 23