HydraFW Bus 3-wire

This guide is updated towards firmware release HydraFW v0.10 and later

Bus: 3-wire
Connections: three pins (SDI/SDA/SCK) and ground
Output types: open drain/open collector
Pull-up resistors: required for open drain output mode (2K – 10K).
Pull-up/down resistors Integrated in MCU: Between 30 to 50K (Typical 40K).
Maximum voltage: 5.5volts (5volt safe)

This is a raw 3-wire communication mode (similar to SPI, but with full pin control)

Protocol configuration syntax description:

• show Show 3-wire parameters or show pins Show pins used in this mode

• pull with parameter up or down or floating to choose internal MCU pull up/down or no pull/external

• frequency with floating frequency value: support k (for kHz), m (for MHz) suffix or no suffix (for Hz)

  • Frequencies available: up to 1MHz

• polarity to select the clock idle level (0 or 1)

• msb-first or lsb-first to send/receive respectively MSB first or LSB first.

• exit to exit 3-wire mode

Note default value: 
    > 3-wire
    Device: threewire1
    GPIO resistor: floating
    Frequency: 1000000Hz
    Bit order: MSB first

Configuration options:

Hardware Informations:

threewire1> show pins 
CLK: PB3
SDI: PB4
SDO: PB5

Protocol configuration example:

Configuration of threewire1 500KHz:

> 3-wire 
Device: threewire1
Frequency : 1000000Hz
threewire1> frequency 500k show 
Device: threewire1
Frequency : 500000Hz

Protocol interaction syntax description:

Bus interaction commands

trigger configures the trigger mode

Protocol interaction example usage threewire1 write/read:

threewire1> 0x01 0x02 ~ r 0x00:4
WRITE: 0x01 0x02 0xFF 
READ: 0xFF
WRITE: 0x00 0x00 0x00 0x00 

Additional informations about 3-wire

For more information about its usage, see : http://dangerousprototypes.com/docs/Raw_3-wire