NUC130LE3CN Nuvoton Technology Corporation of America, NUC130LE3CN Datasheet - Page 371

• Manufacturer Part Number: NUC130LE3CN
• Description: IC MCU 32BIT 128KB FLASH 48LQFP
• Manufacturer: Nuvoton Technology Corporation of America
• Series: NuMicro™ NUC100r

Specifications of NUC130LE3CN

• Core Processor: ARM Cortex-M0
• Core Size: 32-Bit
• Speed: 50MHz
• Connectivity: CAN, I²C, IrDA, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Eeprom Size: -
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 2.5 V ~ 5.5 V
• Data Converters: A/D 8x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.13.4 Functional Description
5.13.4.1 Software Initialization
5.13.4.2 CAN Message Transfer
The software initialization is started by setting the Init bit in the CAN Control Register, either by a
software or a hardware reset, or by going to Bus_Off state.
While the Init bit is set, all messages transfer to and from the CAN bus are stopped and the
status of the CAN_TX output pin is recessive (HIGH). The Error Management Logic (EML)
counters are unchanged. Setting the Init bit does not change any configuration register.
To initialize the CAN Controller, software has to set up the Bit Timing Register and each Message
Object. If a Message Object is not required, the corresponding MsgVal bit should be cleared.
Otherwise, the entire Message Object has to be initialized.
Access to the Bit Timing Register and to the Baud Rate Prescaler Extension Register for
configuring bit timing is enabled when both the Init and CCE bits in the CAN Control Register are
set.
Resetting the Init bit (by software only) finishes the software initialization. Later, the Bit Stream
Processor (BSP) (see Section 5.13.6.10: Configuring the Bit Timing) synchronizes itself to the
data transfer on the CAN bus by waiting for the occurrence of a sequence of 11 consecutive
recessive bits (≡ Bus Idle) before it can take part in bus activities and start the message transfer.
The initialization of the Message Objects is independent of Init and can be done on the fly, but the
Message Objects should all be configured to particular identifiers or set to not valid before the
BSP starts the message transfer.
To change the configuration of a Message Object during normal operation, the software has to
start by resetting the corresponding MsgVal bit. When the configuration is completed, MsgVal is
set again.
Once the C_CAN is initialized and Init bit is reset to zero, the C_CAN Core synchronizes itself to
the CAN bus and starts the message transfer.
Received messages are stored in their appropriate Message Objects if they pass the Message
Handler’s acceptance filtering. The whole message including all arbitration bits, DLC and eight
data bytes are stored in the Message Object. If the Identifier Mask is used, the arbitration bits
which are masked to “don’t care” may be overwritten in the Message Object.
Software can read or write each message any time through the Interface Registers and the
Message Handler guarantees data consistency in case of concurrent accesses.
Messages to be transmitted are updated by the application software. If a permanent Message
Object (arbitration and control bits are set during configuration) exists for the message, only the
data bytes are updated and the TxRqst bit with NewDat bit are set to start the transmission. If
several transmit messages are assigned to the same Message Object (when the number of
Message Objects is not sufficient), the whole Message Object has to be configured before the
transmission of this message is requested.
The transmission of any number of Message Objects may be requested at the same time.
Message objects are transmitted subsequently according to their internal priority. Messages may
be updated or set to not valid any time, even when their requested transmission is still pending.
The old data will be discarded when a message is updated before its pending transmission has
started.
Depending on the configuration of the Message Object, the transmission of a message may be
requested autonomously by the reception of a remote frame with a matching identifier.
NuMicro™ NUC130/NUC140 Technical Reference Manual
- 371 -
Publication Release Date: June 14, 2011
Revision V2.01