* Rename test functions * rewrite furi API, segfault * make fixes in FURI, log through FURI * add uart write example blank * implement fuprintf instead of fopencookie * add gif, blank page * UART write example description Co-authored-by: Vadim Kaushan <admin@disasm.info>
		
			
				
	
	
		
			72 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			72 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
In this example we try to use FURI for interacting between user application and core subsystem.
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First of all, we open FURI record by name "tty". This record is used for send some debug/logging info and interact with user by kind-of-TTY (like UART or USB CDC). By default on Flipper target all writes to tty record handled by debug UART (configured by `DEBUG_UART` define). On local target all writes simply prints to stdout.
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Open record:
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```C
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FuriRecordSubscriber* log = get_default_log();
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```
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This is just wrapper on common FURI method:
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```C
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furi_open("tty", false, false, NULL, NULL);
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```
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"tty" is FURI pipe record. It means that there is no "data" hold in record, it only manage callbacks: when you call `furi_write`, all subscriber's callback is called. You can find default implementation in `core/tty_uart.c`.
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Let's get a look at full example code:
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```C
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#include "flipper.h"
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#include <string.h>
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#include "log.h"
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void application_uart_write(void* p) {
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    // Red led for showing progress
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    GpioPin led = {.pin = GPIO_PIN_8, .port = GPIOA};
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    pinMode(led, GpioModeOpenDrain);
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    // get_default_log open "tty" record
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    FuriRecordSubscriber* log = get_default_log();
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    // create buffer
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    const char test_string[] = "test\n";
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    furi_write(log, test_string, strlen(test_string));
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    // for example, create counter and show its value
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    uint8_t counter = 0;
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    while(1) {
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        // continously write it to UART
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        fuprintf(log, "counter: %d\n", counter);
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        counter++;
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        // flash at every send
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        digitalWrite(led, LOW);
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        delay(50);
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        digitalWrite(led, HIGH);
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        // delay with overall perion of 1s
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        delay(950);
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    }
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}
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```
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This code demonstrates two way to work with record:
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1. Directly writes some data by `furi_write`
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2. Uses `fuprintf` wrapper on `printf`.
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For creating application and set it to autorun, read [Blink example](Blink-app).
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_You can also find source of this example in `applications/examples/uart_write.c` and run it by `docker-compose exec dev make -C target_lo example_uart_write`_
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_Code for target F1 can be compiled by `docker-compose exec dev make -C target_f1 example_uart_write`_
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