PIC18F26K80-E/SP Microchip Technology Inc., PIC18F26K80-E/SP Datasheet - Page 455

• Manufacturer Part Number: PIC18F26K80-E/SP
• Description: 28 SPDIP .300IN TUBE, ECAN, 64KB FLASH, 4KB RAM, 16 MIPS, 12-BIT ADC, CTMU
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F26K80-E/SP

• A/d Inputs: 8-Channel, 12-Bit
• Comparators: 2
• Cpu Speed: 16 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 24
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 64K Bytes
• Ram Size: 3.6K Bytes
• Speed: 64 MHz
• Temperature Range: –40 to 125 °C
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 1.8-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part

FIGURE 27-7:
27.11 Programming Time Segments
Some requirements for programming of the time
segments:
• Prop_Seg + Phase_Seg 1  Phase_Seg 2
• Phase_Seg 2  Sync Jump Width.
For example, assume that a 125 kHz CAN baud rate is
desired, using 20 MHz for F
a baud rate prescaler value of 04h gives a T
To obtain a Nominal Bit Rate of 125 kHz, the Nominal
Bit Time must be 8  s or 16 T
Using 1 T
and 7 T
point at 10 T
Phase Segment 2.
 2011 Microchip Technology Inc.
T
Q
Q
for Phase Segment 1 would place the sample
Q
for the Sync_Seg, 2 T
Q
Sync
after the transition. This leaves 6 T
SHORTENING A BIT PERIOD (SUBTRACTING SJW FROM PHASE SEGMENT 2)
Segment
Prop
OSC
Q
.
. With a T
Q
for the Prop_Seg
OSC
Actual Bit Length
Q
of 500 ns.
of 50 ns,
Segment 1
Phase
Q
Preliminary
Nominal Bit Length
for
Sample Point
PIC18F66K80 FAMILY
By the rules above, the Sync Jump Width could be the
maximum of 4 T
only necessary when the clock generation of the
different nodes is inaccurate or unstable, such as using
ceramic resonators. Typically, an SJW of 1 is enough.
27.12 Oscillator Tolerance
As a rule of thumb, the bit timing requirements allow
ceramic resonators to be used in applications with
transmission rates of up to 125 Kbit/sec. For the full bus
speed range of the CAN protocol, a quartz oscillator is
required. Refer to ISO11898-1 for oscillator tolerance
requirements.
Segment 2
Phase
Q
. However, normally a large SJW is
DS39977C-page 455
 SJW