ESP8266 datasheet(90/117 Pages) ESPRESSIF

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11. UART Introduction

PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_U0CTS);

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Hardware ﬂow control in the receive direction can conﬁgure thresholds,when the

length of rx ﬁfo is greater than the set threshold,U0RTS feet will be pulled to prevent

the other party sending.

Conﬁgured the thresholds of receiving ﬂow control:

The threshold related conﬁgurations are generally deﬁned in UART_CONF1 register.

#deﬁne UART_RX_FLOW_EN (BIT(23)) The 23rd bit enabled to receive ﬂow control: 0:

disable; 1: enable

#deﬁne UART_RX_FLOW_THRHD 0x0000007F //Threshold, occupied 7bit, range 0 ~ 127

#deﬁne UART_RX_FLOW_THRHD_S 16 //Register offset is 16 (start from 16th bit)

•

Once conﬁgure enable of the ﬂow control of sending direction conﬁguration,the

#deﬁne UART_TX_FLOW_EN (BIT(15)) Enable transmission ﬂow control: 0: disable ; 1:

enable

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Interface:

Void UART_SetFlowCtrl(uint8 uart_no,UART_HwFlowCtrl ﬂow_ctrl,uint8 rx_thresh);

e)demo hardware board connections:

Need to connect the J68 (U0CTS) and J63 (U0RTS) jumper .

11.3.11.Other Interfaces

TX_FIFO_LEN(uart_no) //Macro deﬁnition, the current length of the transmit queue

RF_FIFO_LEN(uart_no) //Macro deﬁnition, the current length of the receiving queue

11.4. Conﬁgure Interrupt

Since all interrupt events will be conducted together in the "OR" operation before being

sent to the interrupt controller,UART can only generate an interrupt request each time.By

polling the interrupt state function UART_INT_ST (uart_no),software can deal with multiple

interrupt events in one interrupt service function(multiple if parallel statement).

11.4.1. Interrupt register

Interruption registers in UART:

UART_INT_RAW Interrupt the original status register

UART_INT_ENA Interrupt enable register: Indicates interrupt the current enable UART

UART_INT_ST Interrupt Status Register: Indicates the currently active interrupt status

UART_INT_CLR Clear Interrupt register:set the corresponding bit to clear the interrupt

status register

Espressif

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2017.05

ESP8266 Datasheet(PDF) 90 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.