MOD5234-100IR NetBurner Inc, MOD5234-100IR Datasheet - Page 111

• Manufacturer Part Number: MOD5234-100IR
• Description: MOD5234 10/100 ETHERNET MODULE
• Manufacturer: NetBurner Inc
• Type: Controllers & Processorsr

Specifications of MOD5234-100IR

• Interface: I²C, SPI, UART
• Voltage - Supply: 2.5V
• Mounting Type: Surface Mount
• Package / Case: Module
• Product: Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Format: -
• Baud Rates: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: Q4483564

if MACSR[6:5] == -1/* signed fractional mode */
if MACSR[6:5] == 10/* unsigned integer mode */
The four accumulators are represented as an array, ACCn, where n selects the register.
Although the multiplier array is implemented in a four-stage pipeline, all arithmetic MAC
instructions have an effective issue rate of 1 cycle, regardless of input operand size or type.
All arithmetic operations use register-based input operands, and summed values are stored
internally in an accumulator. Thus, an additional move instruction is needed to store data in a
general-purpose register. One new feature found in EMAC instructions is the ability to choose the
upper or lower word of a register as a 16-bit input operand. This is useful in filtering operations if
one data register is loaded with the input data and another is loaded with the coefficient. Two 16-bit
multiply accumulates can be performed without fetching additional operands between instructions
by alternating the word choice during the calculations.
The EMAC has four accumulator registers versus the MAC’s single accumulator. The additional
registers improve the performance of some algorithms by minimizing pipeline stalls needed to
store an accumulator value back to general-purpose registers. Many algorithms require multiple
calculations on a given data set. By applying different accumulators to these calculations, it is
often possible to store one accumulator without any stalls while performing operations involving
a different destination accumulator.
The need to move large amounts of data presents an obstacle to obtaining high throughput rates in
DSP engines. New and existing ColdFire instructions can accommodate these requirements. A
MOVEM instruction can move large blocks of data efficiently by generating line-sized burst
references. The ability to simultaneously load an operand from memory into a register and execute
a MAC instruction makes some DSP operations such as filtering and convolution more
manageable.
The programming model includes a 16-bit mask register (MASK), which can optionally be used
to generate an operand address during MAC + MOVE instructions. The application of this register
with auto-increment addressing mode supports efficient implementation of circular data queues
for memory operands.
The additional MAC status register (MACSR) contains a 4-bit operational mode field and
condition flags. Operational mode bits control whether operands are signed or unsigned and
whether they are treated as integers or fractions. These bits also control the overflow/saturation
mode and the way in which rounding is performed. Negative, zero, and multiple overflow
condition flags are also provided.
Freescale Semiconductor
Complete Accumulator [47:0] = {ACCextn[15:8], ACCn[31:0], ACCextn[7:0]}
Complete Accumulator[47:0] = {ACCextn[15:0], ACCn[31:0]}
MCF5235 Reference Manual, Rev. 2
General Operation
4-5