Datasheet HT45B3305H (Holtek) - 9

HT45B3305H HT45B3305H CAN Bus Controller CAN Bus Controller SLEEP Mode and Wake-up
The device has an internal SLEEP mode that is used to minimize the current consumption of the device. In the SLEEP Mode the oscillator is turned off. If the I2C serial interface is selected, the I2C interface debounce function will be disabled after entering the SLEEP Mode. To enter the SLEEP mode, the HXTEN bit in the FOCFG register should be cleared to zero. The master can wake up the device by sending a Wake-up command to set the HXTEN bit high and then read the CRHH register (Address: 0x3B) which indicates whether the HXT oscillator is stable after tSTART(HXT) time. If the CRHH has a value of 21H, it means the HXT oscillator is stable and the device is success fully waked-up by the master MCU from the SLEEP mode. START START Control Byte=110x xxxx HXTEN=0 sent via the serial interface HT45B3305H enters SLEEP Mode Waiting tSTART(HXT) for HT45B3305H HXT stable I2C I/F? Yes Turn off Debounce function No Read CAN CRHH register value Receive Control Byte= 110x xxxx No CRHH=0x21? H/W sets HXTEN=1 Yes HT45B3305H HXT is stable HXT starts on and wakes up CAN Next step END
MCU HT45B3305H Functional Description
The Controller Area Network, or CAN bus for short, is a standard communication protocol used originally designed for automotive networking applications, however it is also used in other application areas such as industrial automation and some entertainment products. It is a two wire serial bus to which the CAN bus equipped products are connected together using twisted pair cable with a characteristic impedence of 120Ω.
Write Buffer and Data Check
The device provides a 32-byte Write Buffer with Data check function to easier the communication with Host MCUs and reduce the number of the interface pins between the peripheral device and its Host MCU. SPI I/F HT8 I/F
MCU WRBUF & C_CAN
I2C
DTACHK
I/F Rev. 1.00 8 December 25, 2019 Rev. 1.00 9 December 25, 2019 Document Outline Features Applications General Description Block Diagram Pin Assignment Pin Description Absolute Maximum Ratings D.C. Characteristics A.C. Characteristics System Frequency Characteristics Timing Characteristics Operating Voltage Characteristics Operating Current Characteristics Standby Current Characteristics CAN Electrical Characteristics Power-on Reset Characteristics Power Control Function CLKOUT Pin IDLE Mode SLEEP Mode and Wake-up Functional Description Write Buffer and Data Check SPI and I2C Frame Fields SPI Serial Interface I2C Serial Interface HT45B3305H CAN Block Diagram Interrupt Output Pins Message RAM and FIFO Buffer Configuration HT45B3305H CAN Operating Modes CAN Application Register Description Register Map Register Reset Condition Register Description Application Circuits SPI Serial Interface I2C Serial Interface Package Information 16-pin NSOP (150mil) Outline Dimensions SAW Type 16-pin QFN (3mm×3mm for FP0.25mm) Outline Dimensions