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The more time consuming phase +detection and byte assembly are done in the main code. + +Except at high bitrates, depending on other ongoing activity, +interrupts in particular, this software serial adapter +supports full duplex receive and send. At high bitrates (115200bps) +send bit timing can be improved at the expense of blocking concurrent +full duplex receives, with the +`EspSoftwareSerial::UART::enableIntTx(false)` function call. + +The same functionality is given as the corresponding AVR library but +several instances can be active at the same time. Speed up to 115200 baud +is supported. Besides a constructor compatible to the AVR SoftwareSerial class, +and updated constructor that takes no arguments exists, instead the `begin()` +function can handle the pin assignments and logic inversion. +It also has optional input buffer capacity arguments for byte buffer and ISR bit buffer. +This way, it is a better drop-in replacement for the hardware serial APIs on the ESP MCUs. + +Please note that due to the fact that the ESPs always have other activities +ongoing, there will be some inexactness in interrupt timings. This may +lead to inevitable, but few, bit errors when having heavy data traffic +at high baud rates. + +This library supports ESP8266, ESP32, ESP32-S2 and ESP32-C3 devices. + +## Resource optimization + +The memory footprint can be optimized to just fit the amount of expected +incoming asynchronous data. +For this, the `EspSoftwareSerial::UART` constructor provides two arguments. First, the +octet buffer capacity for assembled received octets can be set. Read calls are +satisfied from this buffer, freeing it in return. +Second, the signal edge detection buffer of 32bit fields can be resized. +One octet may require up to to 10 fields, but fewer may be needed, +depending on the bit pattern. Any read or write calls check this buffer +to assemble received octets, thus promoting completed octets to the octet +buffer, freeing fields in the edge detection buffer. + +Look at the swsertest.ino example. There, on reset, ASCII characters ' ' to 'z' +are sent. This happens not as a block write, but in a single write call per +character. As the example uses a local loopback wire, every outgoing bit is +immediately received back. Therefore, any single write call causes up to +10 fields - depending on the exact bit pattern - to be occupied in the signal +edge detection buffer. In turn, as explained before, each single write call +also causes received bit assembly to be performed, promoting these bits from +the signal edge detection buffer to the octet buffer as soon as possible. +Explaining by way of contrast, if during a a single write call, perhaps because +of using block writing, more than a single octet is received, there will be a +need for more than 10 fields in the signal edge detection buffer. +The necessary capacity of the octet buffer only depends on the amount of incoming +data until the next read call. + +For the swsertest.ino example, this results in the following optimized +constructor arguments to spend only the minimum RAM on buffers required: + +The octet buffer capacity (`bufCapacity`) is 95 (93 characters net plus two tolerance). +The signal edge detection buffer capacity (`isrBufCapacity`) is 11, as each +single octet can have up to 11 bits on the wire, +which are immediately received during the write, and each +write call causes the signal edge detection to promote the previously sent and +received bits to the octet buffer. + +In a more generalized scenario, calculate the bits (use message size in octets +times 10) that may be asynchronously received to determine the value for +`isrBufCapacity` in the constructor. Also use the number of received octets +that must be buffered for reading as the value of `bufCapacity`. +The more frequently your code calls write or read functions, the greater the +chances are that you can reduce the `isrBufCapacity` footprint without losing data, +and each time you call read to fetch from the octet buffer, you reduce the +need for space there. + +## EspSoftwareSerial::Config and parity +The configuration of the data stream is done via a `EspSoftwareSerial::Config` +argument to `begin()`. Word lengths can be set to between 5 and 8 bits, parity +can be N(one), O(dd) or E(ven) and 1 or 2 stop bits can be used. The default is +`SWSERIAL_8N1` using 8 bits, no parity and 1 stop bit but any combination can +be used, e.g. `SWSERIAL_7E2`. If using EVEN or ODD parity, any parity errors +can be detected with the `readParity()` and `parityEven()` or `parityOdd()` +functions respectively. Note that the result of `readParity()` always applies +to the preceding `read()` or `peek()` call, and is undefined if they report +no data or an error. + +To allow flexible 9-bit and data/addressing protocols, the additional parity +modes MARK and SPACE are also available. Furthermore, the parity mode can be +individually set in each call to `write()`. + +This allows a simple implementation of protocols where the parity bit is used to +distinguish between data and addresses/commands ("9-bit" protocols). First set +up EspSoftwareSerial::UART with parity mode SPACE, e.g. `SWSERIAL_8S1`. This will add a +parity bit to every byte sent, setting it to logical zero (SPACE parity). + +To detect incoming bytes with the parity bit set (MARK parity), use the +`readParity()` function. To send a byte with the parity bit set, just add +`MARK` as the second argument when writing, e.g. `write(ch, SWSERIAL_PARITY_MARK)`. + +## Checking for correct pin selection / configuration +In general, most pins on the ESP8266 and ESP32 devices can be used by EspSoftwareSerial, +however each device has a number of pins that have special functions or require careful +handling to prevent undesirable situations, for example they are connected to the +on-board SPI flash memory or they are used to determine boot and programming modes +after powerup or brownouts. These pins are not able to be configured by this library. + +The exact list for each device can be found in the +[ESP32 data sheet](https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf) +in sections 2.2 (Pin Descriptions) and 2.4 (Strapping pins). There is a discussion +dedicated to the use of GPIO12 in this +[note about GPIO12](https://github.com/espressif/esp-idf/tree/release/v3.2/examples/storage/sd_card#note-about-gpio12). +Refer to the `isValidPin()`, `isValidRxPin()` and `isValidTxPin()` +functions in the `EspSoftwareSerial::GpioCapabilities` class for the GPIO restrictions +enforced by this library by default. + +The easiest and safest method is to test the object returned at runtime, to see if +it is valid. For example: + +``` +#include + +#define MYPORT_TX 12 +#define MYPORT_RX 13 + +EspSoftwareSerial::UART myPort; + +[...] + +Serial.begin(115200); // Standard hardware serial port + +myPort.begin(38400, SWSERIAL_8N1, MYPORT_RX, MYPORT_TX, false); +if (!myPort) { // If the object did not initialize, then its configuration is invalid + Serial.println("Invalid EspSoftwareSerial pin configuration, check config"); + while (1) { // Don't continue with invalid configuration + delay (1000); + } +} + +[...] +``` + +## Using and updating EspSoftwareSerial in the esp8266com/esp8266 Arduino build environment + +EspSoftwareSerial is both part of the BSP download for ESP8266 in Arduino, +and it is set up as a Git submodule in the esp8266 source tree, +specifically in `.../esp8266/libraries/SoftwareSerial` when using a Github +repository clone in your Arduino sketchbook hardware directory. +This supersedes any version of EspSoftwareSerial installed for instance via +the Arduino library manager, it is not required to install EspSoftwareSerial +for the ESP8266 separately at all, but doing so has ill effect. + +The responsible maintainer of the esp8266 repository has kindly shared the +following command line instructions to use, if one wishes to manually +update EspSoftwareSerial to a newer release than pulled in via the ESP8266 Arduino BSP: + +To update esp8266/arduino EspSoftwareSerial submodule to lastest master: + +Clean it (optional): +```shell +$ rm -rf libraries/SoftwareSerial +$ git submodule update --init +``` +Now update it: +```shell +$ cd libraries/SoftwareSerial +$ git checkout master +$ git pull +``` diff --git a/src/EspSoftwareSerial/examples/bitpattern/bitpattern.ino b/src/EspSoftwareSerial/examples/bitpattern/bitpattern.ino new file mode 100644 index 0000000..06eb170 --- /dev/null +++ b/src/EspSoftwareSerial/examples/bitpattern/bitpattern.ino @@ -0,0 +1,71 @@ +#include "SoftwareSerial.h" + +#ifndef D5 +#if defined(ESP8266) +#define D8 (15) +#define D5 (14) +#define D7 (13) +#define D6 (12) +#define RX (3) +#define TX (1) +#elif defined(ESP32) +#define D8 (5) +#define D5 (18) +#define D7 (23) +#define D6 (19) +#define RX (3) +#define TX (1) +#endif +#endif + +EspSoftwareSerial::UART swSer; +#ifdef ESP8266 +auto logSer = EspSoftwareSerial::UART(-1, TX); +auto hwSer = Serial; +#else +auto logSer = Serial; +auto hwSer = Serial1; +#endif + +constexpr uint32_t TESTBPS = 115200; + +void setup() { + delay(2000); +#ifdef ESP8266 + hwSer.begin(TESTBPS, ::SERIAL_8N1); + hwSer.swap(); +#else + hwSer.begin(TESTBPS, ::SERIAL_8N1, D6, D5); +#endif + logSer.begin(115200); + logSer.println(PSTR("\nOne Wire Half Duplex Bitpattern and Datarate Test")); + swSer.begin(TESTBPS, EspSoftwareSerial::SWSERIAL_8N1, D6, D5); + swSer.enableIntTx(true); + logSer.println(PSTR("Tx on swSer")); +} + +uint8_t val = 0xff; + +void loop() { + swSer.write((uint8_t)0x00); + swSer.write(val); + swSer.write(val); + auto start = ESP.getCycleCount(); + int rxCnt = 0; + while (ESP.getCycleCount() - start < ESP.getCpuFreqMHz() * 1000000 / 10) { + if (hwSer.available()) { + auto rxVal = hwSer.read(); + if ((!rxCnt && rxVal) || (rxCnt && rxVal != val)) { + logSer.printf(PSTR("Rx bit error: tx = 0x%02x, rx = 0x%02x\n"), val, rxVal); + } + ++rxCnt; + } + } + if (rxCnt != 3) { + logSer.printf(PSTR("Rx cnt error, tx = 0x%02x\n"), val); + } + ++val; + if (!val) { + logSer.println("Starting over"); + } +} diff --git a/src/EspSoftwareSerial/examples/circular_queue_mp_test/mp_queue_test.cpp b/src/EspSoftwareSerial/examples/circular_queue_mp_test/mp_queue_test.cpp new file mode 100644 index 0000000..66c2ac3 --- /dev/null +++ b/src/EspSoftwareSerial/examples/circular_queue_mp_test/mp_queue_test.cpp @@ -0,0 +1,74 @@ +// circular_mp_test.cpp : This file contains the 'main' function. Program execution begins and ends there. +// + +#include +#include +#include +#include +#include "circular_queue/circular_queue_mp.h" + +struct qitem +{ + // produer id + int id; + // monotonic increasing value + int val = 0; +}; + +constexpr int TOTALMESSAGESTARGET = 60000000; +// reserve one thread as consumer +const auto THREADS = std::thread::hardware_concurrency() / 2 - 1; +const int MESSAGES = TOTALMESSAGESTARGET / THREADS; +circular_queue threads(THREADS); +circular_queue_mp queue(threads.capacity()* MESSAGES / 10); +std::vector checks(threads.capacity()); + +int main() +{ + using namespace std::chrono_literals; + std::cerr << "Utilizing " << THREADS << " producer threads" << std::endl; + for (int i = 0; i < threads.capacity(); ++i) + { + threads.push(std::thread([i]() { + for (int c = 0; c < MESSAGES;) + { + // simulate some load + auto start = std::chrono::system_clock::now(); + while (std::chrono::system_clock::now() - start < 1us); + if (queue.push({ i, c })) + { + ++c; + } + else + { + //std::cerr << "queue full" << std::endl; + //std::this_thread::sleep_for(10us); + } + //if (0 == c % 10000) std::this_thread::sleep_for(10us); + } + })); + } + for (int o = 0; o < threads.available() * MESSAGES; ++o) + { + auto now = std::chrono::system_clock::now(); + while (!queue.available()) + { + auto starvedFor = std::chrono::system_clock::now() - now; + if (starvedFor > 20s) std::cerr << "queue starved for > 20s" << std::endl; + //std::this_thread::sleep_for(20ms); + } + auto item = queue.pop(); + if (checks[item.id] != item.val) + { + std::cerr << "item mismatch" << std::endl; + } + checks[item.id] = item.val + 1; + if (0 == item.val % 1000) std::this_thread::sleep_for(100us); + } + while (threads.available()) + { + auto thread = threads.pop(); + thread.join(); + } + return 0; +}