SC16IS752

SC16IS752 is a chip that controls serial ports in some versions of the Wiren Board controllers.

Description

SPI-to-UART bridge IC - NXP SC16IS752

two fully-functional UARTs with hardware flow control, up to 8 GPIOs.

Connected to SPI. GPIO is used as chip-select.

Linux uses the sc16is7x2 driver,which has not been ported to upstream yet. It can be found in our Linux repository [1]. The driver is included in the standard image.

GPIO

sc16is7x2 driver exports 8 GPIOs into the standard Linux sysfs-interface under numbers 120-127.

In Wiren Board Smart Home 3.5

UART0

The device in Linux: /dev/ttyNSC0. Half-duplex RS-485-transceiver. RS-485 port-1 (the green pair of terminals).

The direction of operation of the transceiver is set by the chip using the RTS signal automatically, the hardware flow control must be disabled. RS-485 mode may need to be activated from the userspace in future versions of the driver.

UART1

The device in Linux: /dev/ttyNSC1. Half-duplex RS-485-transceiver. RS-485 port-2 (the blue pair of terminals).

The control signals/GPIO and RX/TX lines are output to the WB SH 3.5: UEXT2 connector.

The connector is designed to use GPIO, as well as to connect the RS232 extension module RS232.

In Wiren Board 2.8

UART0

The device in Linux: /dev/ttyNSC0. TX/RX port lines are output to UEXT UEXT2. A half-duplex RS-485-transceiver(if any) is connected to them in parallel. The direction of operation of the transceiver is set by the chip using the RTS signal automatically, the hardware flow control must be disabled. In future versions of the driver, RS-485 mode may need to be activated from the userspace.

UART1

/dev/ttyNSC1 port in Linux. The SIM68V GPS module is connected to the TX/RX lines of the port.

GPIO

7 GPIO lines are displayed on the holes in increments of 2.54 on the mainboard of the Wiren Board controller. A PPS signal from a GPS modem is connected to one of the GPIO lines.

sc16is7x2 driver exports 8 GPIOs into the standard Linux sysfs-interface under numbers 120-127.