TC35679FSG-002

2018-01-17

16

4.3. UART Interface

4.3.1.

Features

TC35679 UART interface has the following features.



1.8 to 3.6 V operation



Full-duplex four-wire start-stop synchronization data transfer (Reception data, Transmission data, Reception flow control, and

Transmission flow control)



Selectable between 2-line start-stop synchronous transfer (Reception data and Transmission data) and 4-line start-stop

synchronous transfer (Reception data, Transmission data, Reception flow control, and Transmission flow control)



Start bit field (1 bit), data bit field ( 8 bits, LSB first), stop bit field (1 bit), no parity bit



UART transmit and receive data pins can be switched by the command of HCI mode. (UART2 function)



Programmable baud rate: 9600 bps to 921.6 kbps.



3 (or more) character interval should be inserted between one transmission message and another transmission message.

The length of the interval can be changed by a command.



Error detection (Reception character timeout, Reception overrun error, Reception framing error)



Host wake up function

TC35679 communicates commands, status, and data with a host CPU through UART interfaces. The UART interfaces are shared

with GPIO pins, and during boot process after a reset, TC35679 firmware assigns UART functions to the GPIOs. The UART

interfaces can operate at 1.8 to 3.6 V depending on the VDDIO power supply voltage. Because the power supply pin is shared with

UART interface and the other hardware interfaces, UART interface cannot operate at a different voltage from the others.

4.3.2.

Connection Example

TC35679 UART can be connected with an UART interface on a host CPU. Figure 4-4 shows an example of two-wire start-stop

synchronization data transfer connection with an external host CPU. The timing chart to assign the GPIO pins to the UART function

is shown in Figure 4-5.

Figure 4-4 UART connection example

Figure 4-5 Timing for UART function assignment

Reset

UART Transmit data

UART Receive data

Reset

GPIO Configuration

(Pulled up to high)

UART Communication

Output direction

Input direction

TC35679

UART Received Data (RX)

UART Transmitted Data (TX)

HOST CPU