tsoftuart: add a softare timer base UART driver, and example.
This commit is contained in:
Our Air Quality
parent
05da9151ee
commit
5ab0d05768
|
|
@ -0,0 +1 @@
|
|||
!local.mk
|
||||
|
|
@ -0,0 +1,7 @@
|
|||
#define configUSE_TRACE_FACILITY 1
|
||||
#define configGENERATE_RUN_TIME_STATS 1
|
||||
#define portGET_RUN_TIME_COUNTER_VALUE() (RTC.COUNTER)
|
||||
#define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() {}
|
||||
|
||||
/* Use the defaults for everything else */
|
||||
#include_next<FreeRTOSConfig.h>
|
||||
|
|
@ -0,0 +1,13 @@
|
|||
# Makefile for tsfotuart example
|
||||
PROGRAM=tsoftuart
|
||||
EXTRA_COMPONENTS=extras/dhcpserver extras/wificfg extras/mactimer extras/tsoftuart
|
||||
|
||||
# For the mDNS responder included with lwip:
|
||||
EXTRA_CFLAGS += -DLWIP_MDNS_RESPONDER=1 -DLWIP_NUM_NETIF_CLIENT_DATA=1 -DLWIP_NETIF_EXT_STATUS_CALLBACK=1
|
||||
|
||||
# Avoid writing the wifi state to flash when using wificfg.
|
||||
EXTRA_CFLAGS += -DWIFI_PARAM_SAVE=0
|
||||
|
||||
EXTRA_CFLAGS += -DWIFICFG_CLIENT_TASK=1 -DWIFICFG_IRAM_TEST=1
|
||||
|
||||
include ../../common.mk
|
||||
|
|
@ -0,0 +1 @@
|
|||
FLASH_SIZE ?= 32
|
||||
|
|
@ -0,0 +1,75 @@
|
|||
/*
|
||||
* Example timer based software UART drive.
|
||||
*
|
||||
* Copyright (C) 2019 OurAirQuality.org
|
||||
*
|
||||
* Licensed under the Apache License, Version 2.0, January 2004 (the
|
||||
* "License"); you may not use this file except in compliance with the
|
||||
* License. You may obtain a copy of the License at
|
||||
* http://www.apache.org/licenses/
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS WITH THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <string.h>
|
||||
#include <ctype.h>
|
||||
|
||||
#include <espressif/esp_common.h>
|
||||
#include <espressif/user_interface.h>
|
||||
#include <esp/uart.h>
|
||||
#include <FreeRTOS.h>
|
||||
#include <task.h>
|
||||
|
||||
#include "lwip/sockets.h"
|
||||
|
||||
#include "wificfg/wificfg.h"
|
||||
#include "tsoftuart/tsoftuart.h"
|
||||
|
||||
static void tsoftuart_task(void *pvParameters)
|
||||
{
|
||||
/* Initialize the UART Tx. */
|
||||
uint32_t tx_pin = *(uint32_t *)pvParameters;
|
||||
struct tsoftuart *uart = tsoftuart_init(tx_pin, 9600);
|
||||
|
||||
for (;;) {
|
||||
/* Reset the timing error records. */
|
||||
uart->output_queue_error_low = 0;
|
||||
uart->output_queue_error_high = 0;
|
||||
|
||||
char str[] = "Hello 0123456789 abcdefghijklmnopqrstuvwxyz\r\n";
|
||||
for (size_t i = 0; i < strlen(str); i++) {
|
||||
tsoftuart_putc(uart, str[i]);
|
||||
}
|
||||
|
||||
/* Check the timing error. */
|
||||
if (uart->output_queue_error_high > 2 || uart->output_queue_error_low < -2) {
|
||||
tsoftuart_write(uart, "X\r\n", 3);
|
||||
}
|
||||
|
||||
vTaskDelay(200 / portTICK_PERIOD_MS);
|
||||
}
|
||||
}
|
||||
|
||||
void user_init(void)
|
||||
{
|
||||
uart_set_baud(0, 115200);
|
||||
printf("SDK version:%s\n", sdk_system_get_sdk_version());
|
||||
|
||||
wificfg_init(80, NULL);
|
||||
|
||||
/* Start two tasks writing to different pins. */
|
||||
|
||||
static uint32_t tx_pin1 = 1;
|
||||
xTaskCreate(&tsoftuart_task, "tsoftuart1", 256, &tx_pin1, 1, NULL);
|
||||
|
||||
static uint32_t tx_pin2 = 2;
|
||||
xTaskCreate(&tsoftuart_task, "tsoftuart2", 256, &tx_pin2, 1, NULL);
|
||||
}
|
||||
|
|
@ -0,0 +1,10 @@
|
|||
# Component makefile for extras/tsoftuart
|
||||
|
||||
# Expected anyone using tsoftuart includes it as 'tsoftuart/tsoftuart.h'
|
||||
INC_DIRS += $(tsoftuart_ROOT)..
|
||||
|
||||
# args for passing into compile rule generation
|
||||
tsoftuart_INC_DIR =
|
||||
tsoftuart_SRC_DIR = $(tsoftuart_ROOT)
|
||||
|
||||
$(eval $(call component_compile_rules,tsoftuart))
|
||||
|
|
@ -0,0 +1,195 @@
|
|||
/*
|
||||
* Software timer based UART driver.
|
||||
*
|
||||
* Copyright (C) 2018 to 2019 OurAirQuality.org
|
||||
*
|
||||
* Licensed under the Apache License, Version 2.0, January 2004 (the
|
||||
* "License"); you may not use this file except in compliance with the
|
||||
* License. You may obtain a copy of the License at
|
||||
* http://www.apache.org/licenses/
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS WITH THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <stdint.h>
|
||||
#include <sys/types.h>
|
||||
#include <stdlib.h>
|
||||
#include <unistd.h>
|
||||
#include <esp/uart.h>
|
||||
#include <stdio.h>
|
||||
#include <espressif/esp_system.h>
|
||||
#include "FreeRTOS.h"
|
||||
#include "task.h"
|
||||
#include "tsoftuart/tsoftuart.h"
|
||||
|
||||
|
||||
/*
|
||||
* The design builds a sequence of UART output transitions - the delay between
|
||||
* each toggling of the output. This sequence is then followed by a timer and
|
||||
* the timer handler toggles the state and resets the timer for the next
|
||||
* transition until done. This design avoids the code having to spin to
|
||||
* implement delays, and avoid having to disable interrupts for more reliable
|
||||
* timing.
|
||||
*
|
||||
* The MAC timer interrupt is used here as it has a high priority which helps
|
||||
* keep accurate output transition times. The MAC timer interrupt is a NMI and
|
||||
* the handler needs to take care not to interact widely. The handler only
|
||||
* accesses the timer queue, which has already been initialized.
|
||||
*
|
||||
* This software UART is not completely reliable, but might suit debug output
|
||||
* or communication that has an error detection layer, and it is more reliable
|
||||
* at lower baud rates. While it can run up to 115200 baud it is not very
|
||||
* reliable at these higher rates. It is not uncommon for the MAC timer
|
||||
* handler to be delayed 20us, so at UART baud rates above 19200 errors are
|
||||
* expected. This driver attempts to measure the timing errors and this can be
|
||||
* used to help detect when timing errors have occurred.
|
||||
*/
|
||||
|
||||
static void IRAM output_handler(void *arg)
|
||||
{
|
||||
tsoftuart_t *uart = arg;
|
||||
uint32_t tail = uart->output_queue_tail;
|
||||
|
||||
do {
|
||||
uint32_t state = uart->output_queue_state ^ 1;
|
||||
uint64_t current = mactime_get_count();
|
||||
gpio_write(uart->tx_pin, state);
|
||||
uart->output_queue_state = state;
|
||||
|
||||
if (tail == 0) {
|
||||
// First transition.
|
||||
uart->output_start_time = current;
|
||||
uart->output_expected_time = current;
|
||||
}
|
||||
|
||||
/* The difference can be negative because the delay is skipped
|
||||
* if very short, see below. */
|
||||
int32_t err = current - uart->output_expected_time;
|
||||
if (err > uart->output_queue_error_high) {
|
||||
uart->output_queue_error_high = err;
|
||||
}
|
||||
if (err < uart->output_queue_error_low) {
|
||||
uart->output_queue_error_low = err;
|
||||
}
|
||||
|
||||
if (tail >= uart->output_queue_head) {
|
||||
// Done.
|
||||
uart->output_queue_tail = tail;
|
||||
uart->output_done = 1;
|
||||
return;
|
||||
}
|
||||
|
||||
/* Offset from the start. */
|
||||
uint32_t next = uart->output_queue[tail++];
|
||||
uint64_t target = uart->output_start_time + next;
|
||||
uart->output_expected_time = target;
|
||||
/* Target an earlier time, that would not give an error if
|
||||
* actually met, to give more room for the response delay. */
|
||||
target -= 4;
|
||||
int64_t diff = target - current;
|
||||
if (diff >= 0) {
|
||||
uart->output_queue_tail = tail;
|
||||
mactime_add_pending(&uart->output_mactimer, target);
|
||||
break;
|
||||
}
|
||||
} while(1);
|
||||
}
|
||||
|
||||
void tsoftuart_putc(tsoftuart_t *uart, uint8_t ch)
|
||||
{
|
||||
uart->output_queue_state = 1;
|
||||
gpio_write(uart->tx_pin, uart->output_queue_state);
|
||||
|
||||
uart->output_queue_head = 0;
|
||||
uart->output_queue_tail = 0;
|
||||
|
||||
uart->output_queue_error_high = 0;
|
||||
uart->output_queue_error_low = 0;
|
||||
|
||||
uart->output_done = 0;
|
||||
|
||||
uint32_t state = 0;
|
||||
uint32_t count = 1;
|
||||
size_t head = 0;
|
||||
uint32_t cumulative = 0;
|
||||
uint32_t td = uart->td;
|
||||
|
||||
|
||||
for (size_t i = 0; i < 8; i++) {
|
||||
if ((ch & 1) == state) {
|
||||
/* No change */
|
||||
count++;
|
||||
} else {
|
||||
cumulative += count * td;
|
||||
uart->output_queue[head++] = (cumulative + 128) >> 8;
|
||||
state ^= 1;
|
||||
count = 1;
|
||||
}
|
||||
ch >>= 1;
|
||||
}
|
||||
|
||||
if (state == 0) {
|
||||
cumulative += count * td;
|
||||
uart->output_queue[head++] = (cumulative + 128) >> 8;
|
||||
state ^= 1;
|
||||
count = 1;
|
||||
}
|
||||
|
||||
uart->output_queue_head = head;
|
||||
|
||||
/* Trigger the first transition in the future. */
|
||||
mactimer_arm(&uart->output_mactimer, 20);
|
||||
|
||||
/* Wait until the transmittions is expected to have completed. */
|
||||
uint32_t delay = (td * 11 + 128) >> 8;
|
||||
vTaskDelay(((delay / 1000) + portTICK_PERIOD_MS) / portTICK_PERIOD_MS);
|
||||
|
||||
/* Double check that it is done. There is a possibility that the timer has
|
||||
* failed to trigger, and this needed to be detected and the timer removed
|
||||
* from the pending list before retrying. */
|
||||
size_t i;
|
||||
for (i = 0; uart->output_done == 0 && i < 10; i++) {
|
||||
vTaskDelay(1);
|
||||
}
|
||||
|
||||
if (uart->output_done == 0) {
|
||||
/* Remove the timer. */
|
||||
mactimer_disarm(&uart->output_mactimer);
|
||||
/* Set the output high */
|
||||
gpio_write(uart->tx_pin, 1);
|
||||
}
|
||||
}
|
||||
|
||||
ssize_t tsoftuart_write(tsoftuart_t *uart, const void *ptr, size_t len)
|
||||
{
|
||||
for(int i = 0; i < len; i++) {
|
||||
tsoftuart_putc(uart, ((char *)ptr)[i]);
|
||||
}
|
||||
return len;
|
||||
}
|
||||
|
||||
tsoftuart_t *tsoftuart_init(uint8_t tx_pin, uint32_t baud_rate)
|
||||
{
|
||||
tsoftuart_t *uart = malloc(sizeof(tsoftuart_t));
|
||||
|
||||
if (uart) {
|
||||
uart->tx_pin = tx_pin;
|
||||
uart->td = 256000000 / baud_rate;
|
||||
gpio_enable(tx_pin, GPIO_OUTPUT);
|
||||
gpio_set_pullup(tx_pin, true, false);
|
||||
gpio_write(tx_pin, 1);
|
||||
mactimer_init();
|
||||
mactimer_setfn(&uart->output_mactimer, output_handler, uart);
|
||||
}
|
||||
|
||||
return uart;
|
||||
}
|
||||
|
||||
|
|
@ -0,0 +1,47 @@
|
|||
/*
|
||||
* Software timer based UART driver.
|
||||
*
|
||||
* Copyright (C) 2018 to 2019 OurAirQuality.org
|
||||
*
|
||||
* Licensed under the Apache License, Version 2.0, January 2004 (the
|
||||
* "License"); you may not use this file except in compliance with the
|
||||
* License. You may obtain a copy of the License at
|
||||
* http://www.apache.org/licenses/
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS WITH THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
#ifndef _TSOFTUART_H
|
||||
#define _TSOFTUART_H
|
||||
|
||||
#include "mactimer/mactimer.h"
|
||||
|
||||
typedef struct tsoftuart {
|
||||
uint32_t tx_pin;
|
||||
/* Bit time period in usec * 256 */
|
||||
uint32_t td;
|
||||
mactimer_t output_mactimer;
|
||||
uint32_t output_queue[16];
|
||||
volatile uint64_t output_start_time;
|
||||
volatile size_t output_queue_head;
|
||||
volatile size_t output_queue_tail;
|
||||
size_t output_queue_state;
|
||||
uint64_t output_expected_time;
|
||||
int32_t output_queue_error_high;
|
||||
int32_t output_queue_error_low;
|
||||
uint32_t output_done;
|
||||
} tsoftuart_t;
|
||||
|
||||
void tsoftuart_putc(tsoftuart_t *uart, uint8_t ch);
|
||||
ssize_t tsoftuart_write(tsoftuart_t *uart, const void *ptr, size_t len);
|
||||
tsoftuart_t *tsoftuart_init(uint8_t tx_pin, uint32_t baud_rate);
|
||||
|
||||
#endif /* _TSOFTUART_H */
|
||||
Loading…
Reference in New Issue