TC35680FSG datasheet(46/91 Pages) TOSHIBA

46 / 91 page

TC35680FSG-002/TC35681FSG-002

2019-04-04

UART Message Recognition Function (Spacing between Messages)

In order to recognize the boundary of a UART message, a message time space is inserted between the messages transferred

through the UART interface of TC35680/TC35681 in the Complete mode. In the message time space, no data is transferred on the

UART interface. One message consists of one or more frames which exist between two message spaces.

In the HCI mode, the data transfer can be done without the massage time space. But the maximum number of the continuous HCI

command is limited to 8.

The message configured by the frames and the boundary of the message are illustrated in Figure 4-7 (Transmission frame) and

Figure 4-8 (Reception frame). If the space of the neighboring frames is less than 12-frame length (an initial setting), the transmission

data or the reception data is processed as one message. If the space length is 12-frame length or more, the data is processed as

two messages.

The host CPU can recognize the message boundary by measuring the length of the message time space. For example, when the

baudrate is 115.2 kbps, the message time space of the neighboring frames should be (0.087 ms × 12) = 1.04 ms or more (0.087 ms

is one frame time length).

TC35680/TC35681 measure the time space of the neighboring frames using an internal timer to recognize the boundary.

TC35680/TC35681 notify of the reception timeout error when the devices detect a message space time in a message. The default

time of the reception timeout is 12-frame length (1.04ms at 115.2-kbps baud rate) in the User-App mode. This time can be changed

For the reception timeout error, refer to Section 4.7.7.

Figure 4-7 Transmission frame and Transmission message

Figure 4-8 Reception frame and Reception message

UART transmission data

UART transmission

message

UART transmission

message

Less than 12-frame time

12 or more frame time

1-frame time

UART reception data

UART reception message

Less than 12-fram time

Less than 12-frame time

12 or more frame time

1-frame time

TC35680FSG Datasheet(PDF) 46 Page - Toshiba Semiconductor