MOD5234-100IR NetBurner Inc, MOD5234-100IR Datasheet - Page 484

• 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

FlexCAN
21.4.7 Time Stamp
The value of TIMERn is sampled at the beginning of the identifier field on the CAN bus. For a
message being received, the time stamp will be stored in the TIMESTAMP entry of the receive
message buffer at the time the message is written into that buffer. For a message being transmitted,
the TIMESTAMP entry will be written into the transmit message buffer once the transmission has
completed successfully.
The free-running timer can optionally be reset upon the reception of a frame into message buffer
0. This feature allows network time synchronization to be performed. See the
CANCTRLn[TSYN] bit.
21.4.8 Bit Timing
The FlexCAN module CANCTRLn register configures the bit timing parameters required by the
CAN protocol. The CLK_SRC, PRESDIV, RJW, PSEG1, PSEG2, and the PROPSEG fields allow
the user to configure the bit timing parameters.
The CANCTRLn[CLK_SRC] bit defines whether the module uses the internal bus clock or the
output of the crystal oscillator via the EXTAL pin. The crystal oscillator clock should be selected
whenever a tight tolerance (up to 0.1%) is required for the CAN bus timing. The crystal oscillator
clock has better jitter performance than PLL generated clocks. The value of this bit should not be
changed unless the module is in disable mode (CANMCRn[MDIS] bit is set)
The PRESDIV field controls a prescaler that generates the serial clock (S-clock), whose period
defines the “time quantum” used to compose the CAN waveform. A time quantum is the atomic
unit of time handled by the CAN engine.
A bit time is subdivided into three segments
21-30
1.For further explanation of the underlying concepts please refer to ISO/DIS 11519–1, Section 10.3. Reference also the
• SYNC_SEG: This segment has a fixed length of one time quantum. Signal edges are
• Time Segment 1: This segment includes the Propagation Segment and the Phase Segment
Bosch CAN 2.0A/B protocol specification dated September 1991 for bit timing.
expected to happen within this section
1 of the CAN standard. It can be programmed by setting the PROPSEG and the PSEG1
Internal Bus Clock (f
Oscillator Clock (EXTAL)
Figure 21-12. CAN Engine Clocking Scheme
sys/2
)
CANCTRLn[CLK_SRC]
MCF5235 Reference Manual, Rev. 2
1
0
1
(reference
Figure 21-13
Prescaler
(1 .. 256)
and
Table
Freescale Semiconductor
21-15):
S clock