AT90CAN64 Atmel Corporation, AT90CAN64 Datasheet - Page 242

• Manufacturer Part Number: AT90CAN64
• Manufacturer: Atmel Corporation

Specifications of AT90CAN64

• Flash (kbytes): 64 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• Can: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

19.4.3
242
Notes: 1. Phase error < 0
AT90CAN32/64/128
Baud Rate
5. Synchronization Segment: SYNS
2. Phase error > 0
3. Phase error > 0
4. Phase error < 0
Tsyns=1
x
Tscl (
The total number of TQ in a bit time has to be programmed at least from 8 to 25.
Figure 19-7. Sample and Transmission Point
Figure 19-8. General Structure of a Bit Period
With no baud rate prescaler (BRP[5..0]=0) the sampling point comes one time quantum too
early. This leads to a fail according the ISO16845 Test plan. It is necessary to lengthen the
Phase Segment 1 by one time quantum and to shorten the Phase Segment 2 by one time quan-
tum to compensate.
The baud rate selection is made by T
1. Tsyns = 1 x Tscl = (BRP[5..0]+ 1)/clk
2. Tprs = (1 to 8) x Tscl = (PRS[2..0]+ 1) x Tscl
3. Tphs1 = (1 to 8) x Tscl = (PHS1[2..0]+ 1) x Tscl
4. Tphs2 = (1 to 8) x Tscl = (PHS2[2..0]
CLK
fixed
F
Data
CAN
)
IO
CLK
IO
Tbit
Tsyns(5)
(1)
= Tsyns + Tprs + Tphs1 + Tphs2
1
Prescaler BRP
/
CLK
IO
Tscl (TQ)
Tprs
bit
Time Quantum
calculation:
Fcan (Tscl)
Bit Rate Prescaler
IO
one nominal bit
(2)
(= 1TQ)
+ 1) x Tscl
Tbit
Tphs1+Tsjw
Tphs1
PHS1 (3-bit length)
PHS2 (3-bit length)
PRS (3-bit length)
SJW (2-bit length)
Bit Timing
or
(
1
)
(
3
Sample
)
Point
Tphs2+Tsjw
Tphs2
or
Transmission
(
2
Transmission
)
7679H–CAN–08/08
(
Sample
4
)
Point
Point
Point