MA240017 Microchip Technology, MA240017 Datasheet - Page 166

MODULE PLUG-IN PIC24F16KA102 PIM

MA240017

Manufacturer Part Number
MA240017
Description
MODULE PLUG-IN PIC24F16KA102 PIM
Manufacturer
Microchip Technology
Series
PIC®r
Datasheets

Specifications of MA240017

Accessory Type
Plug-In Module (PIM) - PIC24F16KA102
Product
Microcontroller Modules
Data Bus Width
16 bit
Core Processor
PIC24F16KA102
Operating Supply Voltage
3 V to 3.6 V
Development Tools By Supplier
Integrated Development Environment, Assembler, ANSI C Compiler
Processor Series
PIC24F
Silicon Manufacturer
Microchip
Core Architecture
PIC
Core Sub-architecture
PIC24
Silicon Core Number
PIC24F
Silicon Family Name
PIC24FxxKAxx
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With/related Products
Explorer 16 (DM240001 or DM240002)
For Use With
DM240001 - BOARD DEMO PIC24/DSPIC33/PIC32
Lead Free Status / Rohs Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MA240017
Manufacturer:
MICROCHIP
Quantity:
12 000
PIC24F16KA102 FAMILY
FIGURE 20-2:
20.1
20.1.1
To start serial shifting, a value of ‘1’ must be written to
the CRCGO bit.
The module incorporates a FIFO that is 8-level deep
when PLEN<3:0> > 7, and 16 deep, otherwise. The
data for which the CRC is to be calculated must first be
written into the FIFO. The smallest data element that
can be written into the FIFO is one byte.
For example, if PLEN = 5, then the size of the data is
PLEN + 1 = 6. The data must be written as follows:
Once data is written into the CRCWDAT MSb (as
defined by PLEN), the value of the VWORD bits
(CRCCON<12:8>) increments by one. The serial
shifter starts shifting data into the CRC engine when
CRCGO = 1 and VWORD<4:0> > 0. When the Most
Significant bit (MSb) is shifted out, the VWORD bits
decrement by one. The serial shifter continues shifting
until the VWORD bits reach zero. Therefore, for a given
value of PLEN, it will take (PLEN + 1) * VWORD
number of clock cycles to complete the CRC
calculations.
When the VWORD bits reach 8 (or 16), the CRCFUL bit
will be set. When the VWORD bits reach 0, the
CRCMPT bit will be set.
To continually feed data into the CRC engine, the
recommended mode of operation is to initially “prime”
the FIFO with a sufficient number of words so no
interrupt is generated before the next word can be
written. Once that is done, start the CRC by setting the
CRCGO bit to ‘1’. From that point onward, the VWORD
bits should be polled. If they read less than 8 or 16,
another word can be written into the FIFO.
DS39927B-page 164
SDOx
data<5:0> = crc_input<5:0>
data<7:6> = bxx
XOR
User Interface
DATA INTERFACE
D
BIT 0
clk
Q
CRC GENERATOR RECONFIGURED FOR x
D
clk
BIT 4
Q
Preliminary
D
BIT 5
clk
Q
To empty words already written into a FIFO, the
CRCGO bit must be set to ‘1’ and the CRC shifter
allowed to run until the CRCMPT bit is set.
Also, to get the correct CRC reading, it will be
necessary to wait for the CRCMPT bit to go high before
reading the CRCWDAT register.
If a word is written when the CRCFUL bit is set, the
VWORD Pointer will roll over to 0. The hardware will
then behave as if the FIFO is empty. However, the
condition to generate an interrupt will not be met;
therefore, no interrupt will be generated (see
Section 20.1.2 “Interrupt Operation”).
At least one instruction cycle must pass after a write to
CRCWDAT before a read of the VWORD bits is done.
20.1.2
When the VWORD<4:0> bits make a transition from a
value of ‘1’ to ‘0’, an interrupt will be generated.
20.2
20.2.1
If Sleep mode is entered while the module is operating,
the module will be suspended in its current state until
clock execution resumes.
20.2.2
To continue full module operation in Idle mode, the
CSIDL bit must be cleared prior to entry into the mode.
If CSIDL = 1, the module will behave the same way as
it does in Sleep mode; pending interrupt events will be
passed on, even though the module clocks are not
available.
Operation in Power Save Modes
16
INTERRUPT OPERATION
SLEEP MODE
IDLE MODE
+ x
12
CRC Read Bus
D
BIT 12
clk
+ x
Q
5
© 2009 Microchip Technology Inc.
+ 1
CRC Write Bus
BIT 15
D
clk
Q

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