Motor DSP/controller family selected!

[PerBear]

After some investigation, the choice of motor controller family has
been settled:

Microchip dsPIC33F

There are several reasons for selecting this family, here are some of
the most important ones:

- Optimized functionality for brushless and sensorless motor control
- Price
- Available application notes with code for similar application
- Low cost motor control development kits
- Free development SW including C compiler
- Size
- Stand by power consumption
- Availability
- Compatible with DIY soldering (available with 0.8 mm spacing)
- The Nohassel development team has already experience with Microchip
controllers

This is one of the latest DSP families, or DSC as Microchip likes to
call them. In this family there exists 57 different versions, we plan
on using two dsPIC33FJ16MC304, one for each motor, to reduce
complexity of the code.

This sounds like an overkill, buth the selected 40MIPS DSP with 8-
channel motor PWM and bandgap control with everything needed cost less
than USD 2.70 in volume. The 44 pin controller is supplied in two
sizes, 6x6 mm QFN with 0,5 mm spacing, and a 10x10 mm TQFP with 0.8
spacing - TQFP is bigger but better for DIY soldering (0.8 is hard
enough!).

Here are a summary for the MC304 from Microchip:
Operating Range:
Up to 40 MIPS operation (@ 3.0-3.6V):
- Industrial temperature range (-40°C to +85°C)
- Extended temperature range (-40°C to +125°C)
High-Performance DSC CPU:
Modified Harvard architecture
C compiler optimized instruction set
16-bit wide data path
24-bit wide instructions
Linear program memory addressing up to 4M instruction words
Linear data memory addressing up to 64 Kbytes
83 base instructions: mostly 1 word/1 cycle
Two 40-bit accumulators with rounding and saturation options
Flexible and powerful addressing modes:
- Indirect
- Modulo
- Bit-reversed
Software stack
16 x 16 fractional/integer multiply operations
32/16 and 16/16 divide operations
Single-cycle multiply and accumulate:
- Accumulator write back for DSP operations
- Dual data fetch
Up to ±16-bit shifts for up to 40-bit data
Timers/Capture/Compare/PWM:
Timer/Counters, up to three 16-bit timers
- Can pair up to make one 32-bit timer
- 1 timer runs as Real-Time Clock with external
32.768 kHz oscillator
- Programmable prescaler
Input Capture (up to 4 channels):
- Capture on up, down or both edges
- 16-bit capture input functions
- 4-deep FIFO on each capture
Output Compare (up to 2 channels):
- Single or Dual 16-Bit Compare mode
- 16-bit Glitchless PWM mode
Interrupt Controller:
5-cycle latency
118 interrupt vectors
Up to 26 available interrupt sources
Up to 3 external interrupts
7 programmable priority levels
4 processor exceptions
Digital I/O:
Peripheral pin Select functionality
Up to 35 programmable digital I/O pins
Wake-up/Interrupt-on-Change for up to 21 pins
Output pins can drive from 3.0V to 3.6V
Up to 5V output with open drain configuration
All digital input pins are 5V tolerant
4 mA sink on all I/O pins
On-Chip Flash and SRAM:
Flash program memory (up to 32 Kbytes)
Data SRAM (2 Kbytes)
Boot and General Security for program Flash
System Management:
Flexible clock options:
- External, crystal, resonator, internal RC
- Fully integrated Phase-Locked Loop (PLL)
- Extremely low jitter PLL
Power-up Timer
Oscillator Start-up Timer/Stabilizer
Watchdog Timer with its own RC oscillator
Fail-Safe Clock Monitor
Reset by multiple sources
Power Management:
On-chip 2.5V voltage regulator
Switch between clock sources in real time
Idle, Sleep and Doze modes with fast wake-up
Motor Control Peripherals:
6-channel 16-bit Motor Control PWM:
- 3 duty cycle generators
- Independent or Complementary mode
- Programmable dead time and output polarity
- Edge-aligned or center-aligned
- Manual output override control
- 1 Fault input
- Trigger for ADC conversions
- PWM frequency for 16-bit resolution (@ 40 MIPS) = 1220 Hz for Edge-
Aligned mode, 610 Hz for Center-Aligned mode
- PWM frequency for 11-bit resolution (@ 40 MIPS) = 39.1 kHz for Edge-
Aligned mode, 19.55 kHz for Center-Aligned mode
2-channel 16-bit Motor Control PWM:
- 1 duty cycle generator
- Independent or Complementary mode
- Programmable dead time and output polarity
- Edge-aligned or center-aligned
- Manual output override control
- 1 Fault input
- Trigger for ADC conversions
- PWM frequency for 16-bit resolution (@ 40 MIPS) = 1220 Hz for Edge-
Aligned mode, 610 Hz for Center-Aligned mode
- PWM frequency for 11-bit resolution (@ 40 MIPS) = 39.1 kHz for Edge-
Aligned mode, 19.55 kHz for Center-Aligned mode
Quadrature Encoder Interface module:
- Phase A, Phase B and index pulse input
- 16-bit up/down position counter
- Count direction status
- Position Measurement (x2 and x4) mode
- Programmable digital noise filters on inputs
- Alternate 16-bit Timer/Counter mode
- Interrupt on position counter rollover/underflow
Analog-to-Digital Converters (ADCs):
10-bit, 1.1 Msps or 12-bit, 500 Ksps conversion:
- 2 and 4 simultaneous samples (10-bit ADC)
- Up to 6 input channels with auto-scanning
- Conversion start can be manual or
synchronized with 1 of 4 trigger sources
- Conversion possible in Sleep mode
- ±2 LSb max integral nonlinearity
- ±1 LSb max differential nonlinearity
CMOS Flash Technology:
Low-power, high-speed Flash technology
Fully static design
3.3V (±10%) operating voltage
Industrial and Extended temperature
Low power consumption
Communication Modules:
4-wire SPI:
- Framing supports I/O interface to simple codecs
- Supports 8-bit and 16-bit data
- Supports all serial clock formats and sampling modes
I2C™:
- Full Multi-Master Slave mode support
- 7-bit and 10-bit addressing
- Bus collision detection and arbitration
- Integrated signal conditioning
- Slave address masking
UART:
- Interrupt on address bit detect
- Interrupt on UART error
- Wake-up on Start bit from Sleep mode
- 4-character TX and RX FIFO buffers
- LIN bus support
- IrDA® encoding and decoding in hardware
- High-Speed Baud mode
- Hardware Flow Control with CTS and RTS

PerBear