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FM Workbench – Online Developer & Embedded Tools

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Fast, privacy-friendly utilities for software, firmware, and hardware engineering. Convert, calculate, inspect, and debug directly in your browser.

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A compact set of references and calculators that embedded and software engineers reach for often.

ASCII Table

Search decimal, hex, binary, and octal ASCII codes.

ASCIIDEC/HEXBIN
 Checksum Calculator

Calculate XOR, SUM, and LRC checksums for packets.

ChecksumXOR/LRCPacket
 IEEE-754 Converter

Decode float and double values between decimal and hex.

IEEE754Float/DoubleHEX
 SMD Resistor Code

Decode 3-digit, 4-digit, R notation, and EIA-96 markings.

SMD103/4R7EIA-96
 RGB565 Color Picker

Pick HEX and RGB values for embedded TFT/LCD displays.

RGB565HEX/RGBColor
 I2C Pull-up Resistor Calculator

Estimate pull-up ranges from rise time and bus capacitance.

I2CPull-upRise Time

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JSON Formatter format • validate • minify
JSONFormatterParser
 Text Counter chars • bytes • lines
TextCounterBytes
 Base64 / URL Encode·Decode encode • decode
Base64URLEncoding
 Query String Parser url params • decode • query to json
Query StringParserJSON
 Unix Timestamp Converter epoch • UTC
TimestampUTCEpoch
 UUID Generator v1 • v4 • v7 • bulk
UUIDGeneratorv4/v7
 Regex Tester live match • capture groups • cheat sheet
RegexTesterMatch
 Hash Generator MD5 • SHA-1 • SHA-256 • SHA-512
HashMD5/SHADigest
 Diff Viewer text diff • hex compare • Myers algorithm
DiffViewerCompare
 What Is My IP public IP • Cloudflare
IPNetworkLookup
 Image Converter png to jpg • webp to png • format guide
ImageConverterFormats
 PNG to JPG Converter photo optimization • quality tradeoff
PNGJPGConverter
 WEBP to PNG Converter compatibility • transparency workflow
WebPPNGConverter
 IEEE-754 Converter hex ↔ float/double
IEEE754Float/DoubleHEX
 UART Packet Time baud • frame • transfer time
UARTPacket TimeBaud
 UART Baud Error Calculator clock • divider • baud mismatch
UARTBaud ErrorClock
 UART 115200 Error Guide popular baud rate • quick mismatch check
UART115200Error Guide
 UART 8N1 Calculator 10 bits/byte • quick timing
UART8N1Timing
 Hex to Float Converter ieee-754 decode • endian
HEXFloatIEEE754
 HEX ⇄ ASCII ⇄ Binary dump • parse • endian
HEXASCIIBinary
 CRC Calculator CRC8 • CRC16 • CRC32
CRCCRC16/32Protocol
 Checksum Calculator XOR • SUM • LRC
ChecksumXOR/LRCPacket
 Struct Layout offset • padding • pack
StructPaddingOffset
 ASCII Table 0–255 chart • DEC HEX OCT BIN • search & filter
ASCIIDEC/HEXBIN
 Endian Converter byte swap • big ↔ little endian • 8/16/32/64-bit
EndianByte OrderHEX
 I2C Address Converter 7-bit • 8-bit • scanner parse
I2CAddressScanner
 Modbus RTU Timing T1.5 • T3.5 • frame time
ModbusT1.5/T3.5RTU
 Modbus Function Codes 03 · 06 · 16 · exceptions
ModbusFunction CodeException
 Modbus RTU Frame Decoder HEX frame · CRC · function code
Modbus RTUFrame DecodeCRC
 ESP32 LEDC PWM frequency • resolution • duty
ESP32LEDCPWM
 Image to RGB565 Array PNG/JPG • C array • TFT LCD
RGB565C ArrayTFT
 TFT Display Bandwidth FPS • framebuffer • SPI clock
TFT/SPIBandwidthFPS
 MCP2515 Bit Timing CNF1 • CNF2 • CNF3
MCP2515CNF1/2/3CAN
 CAN Bit Timing bitrate • sample point • TQ
CANSample PointTQ
 Color Picker rgb 0-255 • hex • 0xrrggbb • rgb565
RGB565HEX/RGBColor
 Color Code Converter hex ↔ rgb ↔ 0xrrggbb ↔ rgb565
Color CodeHEX/RGBRGB565
 RGB565 to HEX Converter 16-bit color decode • embedded display
RGB565HEXConvert
 LED Resistor Calculator series resistor • power rating
LEDResistorCurrent
 LED Resistor 12V Guide 12v examples • part selection
LED 12VResistorGuide
 SMD Resistor Code 103 • 4R7 • EIA-96
SMD103/4R7EIA-96
 Voltage Divider Vout • current • power
DividerVoutRatio
 I2C Pull-up Resistor Calculator rmin/rmax • rise time • bus capacitance
I2CPull-upRise Time
 I2C Pull-up 3.3V Guide 3.3v bus • practical resistor starting points
I2C 3.3VPull-upGuide
 Ohm's Law Calculator V = IR • power • formula reference
Ohm's LawV=IRPower
 Timer Prescaler Calculator PSC • ARR • MCU timer frequency • error %
TimerPrescalerFrequency
 Capacitor Code Converter 3-digit code • pF • nF • µF • tolerance
CapacitorCodepF/nF
 Wire Gauge Table AWG/SQ • diameter • resistance • current
AWG/SQCurrentDiameter
 Phonetic Alphabet Table A-Z, 0-9 NATO/ICAO phonetic code reference
PhoneticNATOReference
 ADC Code to Voltage raw count • Vref • resolution
ADCCode↔VoltageVref
 NTC Thermistor Calculator R25 · Beta · ADC divider
NTCBetaTemperature
 RS-485 Bias Calculator failsafe • termination • idle voltage
RS-485BiasTermination
 Battery ADC Divider battery voltage · ADC · divider current
BatteryADCDivider
 Thermistor Lookup Table NTC · ADC table · C array
NTCLookup TableC Array
 Stepper Driver Vref A4988 · DRV8825 · current limit
A4988DRV8825Vref

Built for daily work

Fast online tools for developers and embedded engineers

FM Workbench is a curated collection of fast, privacy-friendly online tools for software, firmware, and hardware engineering tasks. All tools run locally in your browser with no tracking or signup. Popular tools include SMD Resistor Code, JSON Formatter, What Is My IP, ASCII Table, Image Converter, I2C Pull-up Calculator, and CRC Calculator.

Tip: Bookmark this page and use the category links above. New tools will appear here as they ship. Ctrl + D