AT90CAN64 Atmel Corporation, AT90CAN64 Datasheet - Page 185

• 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

17.7.2
17.7.3
7679H–CAN–08/08
Sending Frames with 9 Data Bit
Transmitter Flags and Interrupts
If 9-bit characters are used (UCSZn = 7), the ninth bit must be written to the TXB8n bit in UCS-
RnB before the low byte of the character is written to UDRn. The following code examples show
a transmit function that handles 9-bit characters. For the assembly code, the data to be sent is
assumed to be stored in registers R17:R16.
Notes:
The ninth bit can be used for indicating an address frame when using multi processor communi-
cation mode or for other protocol handling as for example synchronization.
The USARTn Transmitter has two flags that indicate its state: USART Data Register Empty
(UDREn) and Transmit Complete (TXCn). Both flags can be used for generating interrupts.
Assembly Code Example
C Code Example
USART0_Transmit:
void USART0_Transmit (unsigned int data)
{
}
; Wait for empty transmit buffer
lds
sbrs
rjmp
; Copy 9th bit from r17-bit0 to TXB80 via T-bit of SREG
lds
bst
bld
sts
; Put LSB data (r16) into buffer, sends the data
sts
ret
/* Wait for empty transmit buffer */
while ( !( UCSR0A & (1<<UDRE0)));
/* Copy 9th bit to TXB8 */
UCSR0B &= ~(1<<TXB80);
if ( data & 0x0100 )
/* Put data into buffer, sends the data */
UDR0 = data;
1. These transmit functions are written to be general functions. They can be optimized if the con-
2. The example code assumes that the part specific header file is included.
UCSR0B |= (1<<TXB80);
tents of the UCSR0B is static. For example, only the TXB80 bit of the UCSRB0 Register is
used after initialization.
r18, UCSR0A
r18, UDRE0
USART0_Transmit
r18, UCSR0B
r17, 0
r18, TXB80
UCSR0B, r18
UDR0, r16
(1)(2)
(1)(2)
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