Switch to fast serial.

Should be backwards compatible, except that commands ending in just newline (\n) are accepted in addition to commands ending in carriage return + newline (\r\n).

prawnblaster/CMakeLists.txt

@@ -1,34 +1,30 @@
 add_executable(prawnblaster
         prawnblaster.cpp
+        fast_serial.c
         )
 
 pico_generate_pio_header(prawnblaster ${CMAKE_CURRENT_LIST_DIR}/pseudoclock.pio)
 
 
 # Pull in our pico_stdlib which aggregates commonly used features
-target_link_libraries(prawnblaster pico_stdlib hardware_pio pico_multicore hardware_clocks hardware_dma)
-
-# enable usb output, disable uart output
-pico_enable_stdio_usb(prawnblaster 1)
-pico_enable_stdio_uart(prawnblaster 0)
+target_link_libraries(prawnblaster pico_stdlib hardware_pio pico_multicore pico_unique_id hardware_clocks hardware_dma tinyusb_device tinyusb_board)
+target_include_directories(prawnblaster PRIVATE .)
 
 # create map/bin/hex/uf2 file etc.
 pico_add_extra_outputs(prawnblaster)
 
 add_executable(prawnblasteroverclock
         prawnblaster.cpp
+        fast_serial.c
         )
 
 pico_generate_pio_header(prawnblasteroverclock ${CMAKE_CURRENT_LIST_DIR}/pseudoclock.pio)
 
 set_target_properties(prawnblasteroverclock PROPERTIES COMPILE_DEFINITIONS PRAWNBLASTER_OVERCLOCK=1)
 
 # Pull in our pico_stdlib which aggregates commonly used features
-target_link_libraries(prawnblasteroverclock pico_stdlib hardware_pio pico_multicore hardware_clocks hardware_dma)
-
-# enable usb output, disable uart output
-pico_enable_stdio_usb(prawnblasteroverclock 1)
-pico_enable_stdio_uart(prawnblasteroverclock 0)
+target_link_libraries(prawnblasteroverclock pico_stdlib hardware_pio pico_multicore pico_unique_id hardware_clocks hardware_dma tinyusb_device tinyusb_board)
+target_include_directories(prawnblasteroverclock PRIVATE .)
 
 # create map/bin/hex/uf2 file etc.
-pico_add_extra_outputs(prawnblasteroverclock)
+pico_add_extra_outputs(prawnblasteroverclock)

prawnblaster/fast_serial.c

@@ -0,0 +1,198 @@
+#include "tusb.h"
+#include "pico/unique_id.h"
+
+#include <stdarg.h>
+
+#include "fast_serial.h"
+
+/*
+  Serial functions
+
+  These are mostly thin wrappers around TinyUSB functions;
+  they are provided to simplify the API.
+ */
+
+// Read bytes (blocks until buffer_size is reached)
+uint32_t fast_serial_read(const char * buffer, uint32_t buffer_size){
+	uint32_t buffer_idx = 0;
+	while(buffer_idx < buffer_size){
+		uint32_t buffer_avail = buffer_size - buffer_idx;
+		uint32_t read_avail = fast_serial_read_available();
+
+		if(read_avail > 0){
+			if(buffer_avail > read_avail){
+				buffer_avail = read_avail;
+			}
+
+			buffer_idx += fast_serial_read_atomic(buffer + buffer_idx, buffer_avail);
+		}
+
+		fast_serial_task();
+	}
+	return buffer_size;
+}
+
+// Read bytes until terminator reached (blocks until terminator or buffer_size is reached)
+uint32_t fast_serial_read_until(char * buffer, uint32_t buffer_size, char until){
+	uint32_t buffer_idx = 0;
+	while(buffer_idx < buffer_size){
+		while(fast_serial_read_available() > 0){
+			int32_t next_char = tud_cdc_read_char();
+
+			buffer[buffer_idx] = next_char;
+			buffer_idx++;
+			if(next_char == until){
+				break;
+			}
+		}
+
+		if(buffer_idx > 0 && buffer[buffer_idx-1] == until){
+			break;
+		}
+		fast_serial_task();
+	}
+	return buffer_idx;
+}
+
+// Write bytes (without flushing, so limited to 64 bytes)
+uint32_t fast_serial_write(const char * buffer, uint32_t buffer_size){
+	uint32_t buffer_idx = 0;
+	while(buffer_idx < buffer_size){
+		uint32_t write_avail = fast_serial_write_available();
+
+		if(write_avail > 0){
+			if(buffer_size - buffer_idx < write_avail){
+				write_avail = buffer_size - buffer_idx;
+			}
+
+			buffer_idx += fast_serial_write_atomic(buffer + buffer_idx, write_avail);
+		}
+		fast_serial_task();
+		fast_serial_write_flush();
+	}
+	return buffer_size;
+}
+
+int fast_serial_printf(const char * format, ...){
+	va_list va;
+	va_start(va, format);
+	char printf_buffer[128];
+	int ret = vsnprintf(printf_buffer, 128, format, va);
+	va_end(va);
+	if(ret <= 0){
+		return ret;
+	}
+	return fast_serial_write(printf_buffer, strnlen(printf_buffer, 128));
+}
+
+/*
+  USB callbacks
+*/
+
+void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts){}
+void tud_cdc_rx_cb(uint8_t itf){}
+
+/*
+  USB descriptor setup
+
+  We use the same VID, PID and ID as the Pi Pico would normally use.
+ */
+tusb_desc_device_t const desc_device = {
+    .bLength            = sizeof(tusb_desc_device_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE,
+    .bcdUSB             = 0x0200,
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+
+    .idVendor           = 0x2E8A,
+    .idProduct          = 0x000A,
+    .bcdDevice          = 0x0100,
+
+    .iManufacturer      = 0x01,
+    .iProduct           = 0x02,
+    .iSerialNumber      = 0x03,
+
+    .bNumConfigurations = 0x01
+};
+
+uint8_t const * tud_descriptor_device_cb(){
+	return (uint8_t const *) &desc_device;
+}
+
+enum{
+	ITF_NUM_CDC = 0,
+	ITF_NUM_CDC_DATA,
+	ITF_NUM_TOTAL
+};
+
+#define EPNUM_CDC_NOTIF 0x81
+#define EPNUM_CDC_OUT 0x02
+#define EPNUM_CDC_IN 0x82
+
+#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)
+
+uint8_t const desc_configuration[] = {
+	// Config number, interface count, string index, total length, attribute, power in mA
+	TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+// Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+	TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64)
+};
+
+uint8_t const * tud_descriptor_configuration_cb(uint8_t index){
+	return desc_configuration;
+}
+
+enum {
+	STRID_LANGID = 0,
+	STRID_MANUFACTURER,
+	STRID_PRODUCT,
+	STRID_SERIAL,
+};
+
+static char usb_serial_str[PICO_UNIQUE_BOARD_ID_SIZE_BYTES * 2 + 1];
+
+char const* string_desc_arr [] ={
+	(const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+	"Raspberry Pi",                      // 1: Manufacturer
+	"Pico",            // 2: Product
+	usb_serial_str,                      // 3: Serials, should use chip ID
+	"Board CDC", // 4: CDC Interface
+};
+
+static uint16_t _desc_str[32];
+
+uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid){
+	uint8_t chr_count;
+
+	if(!usb_serial_str[0]){
+		pico_get_unique_board_id_string(usb_serial_str, sizeof(usb_serial_str));
+	}
+
+	if(index == 0){
+		memcpy(&_desc_str[1], string_desc_arr[0], 2);
+		chr_count = 1;
+	}
+	else{
+		if(!(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0]))){
+			return NULL;
+		}
+
+		const char* str = string_desc_arr[index];
+
+		// Cap at max char
+		chr_count = (uint8_t) strlen(str);
+		if ( chr_count > 31 ) chr_count = 31;
+
+		// Convert ASCII string into UTF-16
+		for(uint8_t i = 0; i < chr_count; i++){
+			_desc_str[1+i] = str[i];
+		}
+	}
+
+	// first byte is length (including header), second byte is string type
+	_desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8 ) | (2*chr_count + 2));
+
+	return _desc_str;
+}

prawnblaster/fast_serial.h

@@ -0,0 +1,75 @@
+/*
+  Faster serial functions
+
+  fast_serial_read/fast_serial_read_until are blocking functions
+  designed to receive data over a USB serial connection as fast as possible
+  (hopefully at the limit of the drivers).
+  fast_serial_read is generally much faster (~4x) than fast_serial_read_until,
+  as it can read larger blocks of data without having to scan for the terminating character.
+  Therefore, it is recommended to use fixed size blocks for large transmissions.
+
+  fast_serial_write is a blocking function
+  designed to send data over a USB serial connection as fast as possible
+  (again hopefully at the limit of the drivers).
+
+  The remaining functions are thin wrappers around TinyUSB functions;
+  they are provided to simplify the API.
+
+  Basic usage:
+  Call fast_serial_init()
+  In the main processing loop, call fast_serial_task.
+  Place calls to fast_serial_read/fast_serial_read_until and fast_serial_write where appropriate.
+ */
+#include "tusb.h"
+
+// Initialize the USB stack
+static inline bool fast_serial_init(){
+	return tusb_init();
+}
+
+// Get number of bytes available to read
+static inline uint32_t fast_serial_read_available(){
+	return tud_cdc_available();
+}
+
+// Get number of bytes available to write
+static inline uint32_t fast_serial_write_available(){
+	return tud_cdc_write_available();
+}
+
+// Read up to 64 bytes
+static inline uint32_t fast_serial_read_atomic(char * buffer, uint32_t buffer_size){
+	return tud_cdc_read(buffer, buffer_size);
+}
+
+// Read bytes (blocks until buffer_size is reached)
+uint32_t fast_serial_read(const char * buffer, uint32_t buffer_size);
+
+// Read bytes until terminator reached (blocks until terminator or buffer_size is reached)
+uint32_t fast_serial_read_until(char * buffer, uint32_t buffer_size, char until);
+
+// Clear read FIFO (without reading it)
+static inline void fast_serial_read_flush(){
+	tud_cdc_read_flush();
+}
+
+// Write bytes (without flushing, so limited to 64 bytes)
+static inline uint32_t fast_serial_write_atomic(const char * buffer, uint32_t buffer_size){
+	return tud_cdc_write(buffer, buffer_size);
+}
+
+// Write bytes (without flushing)
+uint32_t fast_serial_write(const char * buffer, uint32_t buffer_size);
+
+// print via fast_serial_write
+int fast_serial_printf(const char * format, ...);
+
+// Force write of data. Returns number of bytes written.
+static inline uint32_t fast_serial_write_flush(){
+	return tud_cdc_write_flush();
+}
+
+// Must be called regularly from main loop
+static inline void fast_serial_task(){
+	tud_task();
+}