SC16IS752/en

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

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

Устройство в Linux: /dev/ttyNSC0. TX/RX линии порта выведены на разъём UEXT UEXT2. Параллельно к ним подключен полудуплексный RS-485-трансивер (если есть). Направление работы трансивер задаётся чипом с помощью сигнала RTS автоматически, аппаратный контроль потока должен быть отключен. В следующих версиях драйвера, режим RS-485 возможно будет необходимо активировать из userspace.

UART1

Порт /dev/ttyNSC1 в Linux. К TX/RX-линиям порта подключен GPS-модуль SIM68V.

GPIO

7 линий GPIO выведены на отверстия с шагом 2.54 на плате Wiren Board. К одной из линий GPIO подключен сигнал PPS с GPS-модема.

Драйвер sc16is7x2 экспортирует 8 GPIO в стандартный sysfs-интерфейс Linux под номерами 120-127.