TMC4210 DATASHEET (Rev. 1.03 / 2015-JUN-03)
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5 Control Interface
The communication takes place via a four wire serial interface and 32 bit datagrams of fixed length.
RESPONSIBILITIES ARE DEFINED AS FOLLOWS:
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The microcontroller is the master of the TMC4210. It initializes the motion controller and sets
target values for velocity, acceleration, and positioning.
The TMC4210 is the master of the stepper motor driver. The motion controller calculates, e.g.,
ramp profiles for positioning. It sends step and direction signals to the stepper motor driver.
The microcontroller initializes the stepper motor driver. Further, the microcontroller can read out
status and error flags and thus make the diagnostics.
AUTOMATIC POWER-ON RESET:
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The TMC4210 cannot be accessed before the power-on reset is completed and the clock is stable.
All register bits are initialized with 0 during power-on reset, except the Step/Dir clock pre-devider
STPDIV_4210 that is initialized with 15.
5.1 Bus Signals
Signal Description
TMC4210
SCK_C
SDI_C
SDO_C
nSCS_C
Microcontroller
Bus clock input
Serial data input
Serial data output
Chip select input
5.2 Serial Peripheral Interface for µC
The serial microcontroller interface of the TMC4210 acts as a 32 bit shift register.
COMMUNICATION BETWEEN µC AND THE TMC4210
1. The serial µC interface shifts serial data into SDI_C with each rising edge of the clock signal
SCK_C.
2. Then, it copies the content of the 32 bit shift register into a buffer register with the rising
edge of the selection signal nSCS_C.
3. The serial interface of the TMC4210 immediately sends back data read from registers or read
from internal RAM via the signal SDO_C.
4. The signal SDO_C can be sampled with the rising edge of SCK_C. SDO_C becomes valid at
least four CLK clock cycles after SCK_C becomes low as outlined in the timing diagram.
5.2.1 Timing
A complete serial datagram frame has a fixed length of 32 bit. Because of on-the-fly processing of the
input data stream, the serial µC interface of the TMC4210 requires the serial data clock signal SCK_C to
have a minimum low / high time of three clock cycles. The SPI signals from the µC interface may be
asynchronous to the clock signal CLK of the TMC4210.
If the microcontroller and the TMC4210 work on different clock domains that run asynchronously by
the timing of the SPI interface of the microcontroller should be made conservative in the way that
the length of one SPI clock cycle equals 8 or more clock cycles of the TMC4210 clock CLK.
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TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
