Presentation
This repository contains an alternate and free firmware for the DFRobot DFR0592 DC Motor Driver Hat.
License
This software is released under the terms of the GNU General Public License version 3. See the COPYING file for the full license text.
Hardware
Board DC Motor Driver Hat DFRobot DFR0592
Microcontroller STM32F103C8T6 (medium density)
Useful onboard peripherals
| Peripheral | N |
|---|---|
| Flash | 64kiB |
| RAM | 20kiB |
| Timers (general purpose) | |
| Timers (advanced control) | |
| CPU frequency | 72MHz |
| I2C |
The I2C2 is used (PB10/SCL, PB11/SDA) to communicate with
the TB6612FNG motor driver.
Flash-memory organization
- Main memory: 64 pages of 1KiB
- Page erasable
- Programmable by half-words
-
VTORmust be aligned with the number of exception entries or 128 bits, whichever is largest. To use all DMA channels (DMA2_Channel4_5is at position 59), an alignment of 256 is required. In any case, aligning it on a page boundary will work.
Driver IC TB6612FNG for dual DC motor
Encoders FIT0450
Led pattern
The led pattern is in Morse code.
| Code | Meaning | Pattern |
|---|---|---|
| I | Regular mode | .. |
| LP | Low power (Vdd is below 2.9V) | .-.. .--. |
| WW | Last reset was due to the window watchdog trigerring | .-- .-- |
Bootloader
A I²C bootloader is available so that the firmware can be reprogrammed
from the host (typically a Raspberry Pi) using the firmware-updater
program.
When the bootloader is used, the flash is split into two parts:
- 24KiB for the bootloader
- 40KiB for the firmware
The firmware will be compiled with a layout compatible with the
bootloader if the bootloader feature is activated, which is the
default.
Motor controller command set
I²C address: 0x57
I²C uses clock stretching, so care must be taken when using a Raspberry Pi whose SOC is bogus. Using 400kHz instead of the default 100kHz seems to mask the problem if not outputting too much debug information. Using a software I²C solves the issue.
Multibyte values are exchanged in little endian format.
0x08 Firmware version (R)
- 3 bytes containing the major, minor and patch version numbers
derived from
Cargo.toml.
0x0F Who am I? (R)
- The I²C address (1 byte)
0x10 PWM frequency (R/W)
+- Frequency in Hz on 3 bytes, from 1 to 100_000 (default: 20_000)
0x20-0x22 PID coefficients (R/W)
The PID will be working at 100Hz.
P, I and D are expressed as 32 bit signed numbers with a 24 bit integer part and a 8 bit fractional part.
- 0x20: P (4 bytes). Default value is 0x0000_0040 (0.25)
- 0x21: I (4 bytes). Default value is 0x0000_0000 (0.0)
- 0x22: D (4 bytes). Default value is 0x0000_0000 (0.0)
Changing the coefficients will take effect only when the controlled mode is off, for example by setting the motors to standby mode.
0x28 Motor shutdown timeout (R/W)
- Number of tenths of seconds in before the motor shut down (1 byte). The minimum is 1 (0.1 seconds) and the maximum is 100 (10 seconds).
0x30 Raw motor speed (R/W)
- Left and right motor speed, between -100 and 100 each (1 byte each), max speed is ±100. None means standby. ±100 corresponds to the value limited by the max motor percentage.
- This is the raw speed sent to the motor, no PID is computed.
- If written while in controlled mode, the robot switches to manual mode
0x31 Controlled motor speed (R/W)
- Left and right motor speed, beween -32767 and 32767 each (2 bytes each). The unit is the number of ticks per 100th of seconds.
- Each motor will be controlled by a separate PID with shared coefficients.
- Using a speed of (0, 0) will exit the controlled mode and switch to raw mode. This allows the PID coefficients to be updated if needed.
- Speed will be returned as (-32768, -32768) if controlled mode is not active.
0x32 Encoder ticks (R)
- Left and right encoder counters since last time, between -32768 and 32767 (2 bytes each).
0x36 Status byte (R)
- Bit 0: moving (1) or idle (0)
- Bit 1: controlled mode (1) or raw mode (0)
0xE0 Reset (W)
- Reset the device. Used mainly for testing.
0xE1 Reset to bootloader (W) [only if bootloader feature is enabled]
- Reset the device in bootloader mode. Used when reprogramming.
0xF0 Unique device ID (R)
- Unique device ID as found in addresses 0x1FFFF7E8-0x1FFFF7EF (8 bytes)
0xF1 Device family (R)
- Identity code code (1 byte)
- Continuation code (1 byte)
If they cannot be read, they are returned as zeroes.
0xF2 MCU kind (R)
- Device ID from the
IDCODEfield of theDBGMCUregister (1 byte) - Revision ID from the
IDCODEfield of theDBGMCUregister (1 byte)
It might happen that an incorrect value is returned on STM32 devices when no SWD or JTAG probe is connected.
0xF3 Flash size (R)
- Internal flash size as declared by the microcontroller (2 bytes)
0xFE Firmware capabilities byte (R)
- Bit 0: bootloader feature is activated
Bootloader command set
If a firmware is present, the bootloader will start it unless the firmware has explicitly chosen to reboot in bootloader mode.
I²C address: 0x57
The note about clock stretching also applies for the bootloader.
0x08 Firmware version (R)
- 3 bytes containing the major, minor and patch version
numbers derived from
Cargo.toml.
0x0F Who am I? (R)
- The I²C address with the highest bit set: 0xd7 (1 byte)
0x10 Status (R)
Returns 2 bytes:
- One set of flags ORed together:
- 0x01: system is in programming mode
- 0x02: at least one error was detected since the last time the system has been put in programming mode
- 0x04: a program is currently present in flash
- A XORed version of all data received so far since the programming address was last set, either by entering programming mode, or by using the SET PROGRAMMING ADDRESS command.
0x20 Change programming mode (W)
- [0x00]: leave programming mode without marking the application as succesfully written [programming mode only]
- [0x01]: leave programming mode and mark the application as succesfully written [programming mode only]
- [0x17, 0x27, 0x65, 0x40]: enter programming mode
0x24 Erase pages (W) [programming mode only]
- First byte: index of the first 1kB page in the application area
- Second byte: number of pages to erase (up to the end of the application area)
- Third byte: XOR of the first two bytes, as a safety
The memory will be erased. The active programming address is then set to the beginning of the erased area.
Even if the last page of the application does not belong to the erased page set, it will be erased with the first erase request of the current session (or after having being set again) to ensure that the application is no longer considered valid.
Designating address outside the application area, or having a wrong checksum, will be an error.
0x28 Set programming address (W) [programming mode only]
- 4 bytes containing the next address to program, relative to the application start
- 1 byte XORing the previous ones
0x2c Program data (W) [programming mode only]
- 2, 4, 6, or 8 data bytes
- 1 byte XORing the previous ones
In case of error, the bootloader leaves programming mode immediately.
The programming address will advance with the right number of bytes.
0x30 Read memory (R) [programming mode only]
- Read 8 consecutive bytes in memory from the programming address (relative to the application start), and advance it by 8.
0 will be returned outside the application memory area.
0x34 Set checksum (W) [programming mode only]
- Set the checksum value to the given byte.
0xE0 Reset (W)
- Reset the bootloader in automatic mode
0xE1 Reset to the bootloader (W)
- Reset the bootloader in bootloader mode
0xE2 Reset to the application (W)
- Reset the bootloader in application mode
0xF0 Unique device ID (R)
- Unique device ID as found in addresses 0x1FFFF7E8-0x1FFFF7EF (8 bytes)
0xF1 Device family (R)
- Identity code code (1 byte)
- Continuation code (1 byte)
If they cannot be read, they are returned as zeroes.
0xF2 MCU kind (R)
- Device ID from the
IDCODEfield of theDBGMCUregister (1 byte) - Revision ID from the
IDCODEfield of theDBGMCUregister (1 byte)
It might happen that an incorrect value is returned on STM32 devices when no SWD or JTAG probe is connected.
0xF3 Flash size (R)
- Internal flash size as declared by the microcontroller (2 bytes)