Link to this headingUART

Link to this headingFinding Info

Common Baud Rates:

  1. 9600 (about 104.2 µs per bit)
  2. 38400 (about 26.04 µs per bit)
  3. 19200 (about 52.08 µs per bit)
  4. 57600 (about 17.36 µs per bit)
  5. 115200 (about 8.681 µs per bit)

When device is off:

  • Vcc: INF resistance
  • Tx: 80kΩ
  • Rx: 12kΩ
  • GND: 0Ω

When device is on:

  • Vcc: 3.3V
  • Tx: 1.7-2.5V
  • Rx: 0-0.004V
  • GND: 0Ω

Link to this headingFinding Baudrate

Using Saleae Logic Analyzer:

  1. Start the Saleae Analyzer
    • Set to at least 50 MS/s
    • Set Duration for 30 seconds
    • Set Channel 0 for Trigger on Falling Edge
  2. Click on the + next to Analyzers Select Async Serial

Using Logic Analyzer:

  1. Set the capture length to 20 M Samples
  2. Set the capture rate to 1 MHz
  3. Click on the + next view to UART
  4. Set Ports to the correct RX and TX
  5. Set to ascii instead of hex to view the data.
  6. Optional Change the baudrate.

Using Software:

Using the Script:

>>> python baudrate.py {'baudrate': 9600, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} [-] Invalid: Baudrate: 4000000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 3500000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 3000000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 2500000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 2000000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 1500000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 1152000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 1000000 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 921600 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 576000 | Parity: N | StopBits: 1 | ByteSize: 8 b'xxxxx<xxxxxxxxxxxxxx<xxxx' {'baudrate': 500000, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'xxxxxxxxxxxxxxxxxxxxxxxxx' {'baudrate': 460800, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'`fff~f`f~`f`~``fxf`fxff`f' {'baudrate': 230400, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'fxfxxxxpL\x0c\x0c@\x0c\x0c\x0c\r\nErased 1' {'baudrate': 115200, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'h)\x0b\x0c:X\tS::xZ[\ry,\t9yi:X\t8Z' {'baudrate': 57600, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'^:9z.)!k;!,gRrV98-1@J`hHZ' {'baudrate': 38400, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b"hJP'|\tpC_Y4AD\\PHYCMTL]BQX" {'baudrate': 19200, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'YUEVPUBa\rLQ%D5%\r5%5%=O)Eu' {'baudrate': 9600, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} b'Ef88\rf980C|8u.P 4`QP4 06"' {'baudrate': 4800, 'bytesize': 8, 'parity': 'N', 'stopbits': 1, 'xonxoff': False, 'dsrdtr': False, 'rtscts': False, 'timeout': 5, 'write_timeout': None, 'inter_byte_timeout': None} [-] Invalid: Baudrate: 2400 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 1800 | Parity: N | StopBits: 1 | ByteSize: 8 [-] Invalid: Baudrate: 1200 | Parity: N | StopBits: 1 | ByteSize: 8

Link to this headingConnecting to Tigard

Connecting using a Tigard:

screen /dev/ttyUSB0 115200

Link to this headingDump Flash

ar7240> md.b [Start Flash address] [Flash Size] ar7240> md.b 9F000000 0x400000