Datasheet

TMC8460-BI Datasheet (V100 / 2016-Sep-01)
Copyright © 2016 TRINAMIC Motion Control GmbH & Co. KG 20
3 Device Usage and Handling
3.1 Sample Block Diagrams
The TMC8460 allows for flexible system architectures using a microcontroller running the Slave Stack
Code (SSC) or using Device Emulation mode without a microcontroller.
The following examples show typical system architectures using the TMC8460.
3.1.1 Typical EtherCAT Slave architecture
The first application diagram shows the TMC8460 in a typical straightforward architecture. The PHYs
connect to the TMC8460 using MII interface. Both PHYs and the TMC8460 have the same 25MHz clock
source (see Section 3.9.2). The I2C EEPROM is connected to the TMC8460 and contains boot-up
configuration required by the ESC after reset or power-cycling. The EEPROM is optionally connected to
the µC to allow EEPROM updates via the MCU’s firmware.
The µC connects to the TMC8460 using an SPI bus interface to the PDI SPI. The local application is
connected to the µC and is controlled by the application layer inside the µC. The application interface
depends on the application and is a generic placeholder in this diagram. In this example the MFCIO IO
block is not used.
100
Mbit
ETH PHY
TMC8460-BI
µC / Application
Controller
with Slave Stack
Code
EEPROM
MII
MII
I2C
RJ45
+
Transformer
100
Mbit
ETH PHY
RXTX
I2C
RXTX
MFCIO Block
PDI SPI
25MHz
source
Local application
Figure 6 - Application diagram using only the local application controller to interface the application
3.1.2 MFCIO block based Microcontroller Architecture
The second application diagram shows a similar architecture with µC but with extensive use of the
MFCIO block features. The special functions of the MFCIO block allow relocating functionality from the
µC to the TMC8460. That is, certain compute intense and time-critical functions are moved from software
to hardware. The application layer in the µC can focus on interfacing to the real-time bus and for high-
level control tasks of the application.
For example, an incremental encoder can directly be connected to the MFCIO block. The µC only reads
back the actual position via the dedicated SPI interface MFC CTRL SPI. Additionally, SPI slave chips are
directly connected to the MFCIO and not the µC, for example Trinamic’s dedicated smart stepper motor
drivers, dedicated hardware motion controllers, and simple S/D stepper motor drivers. The MFCIO block
master SPI interface, the PWM functions, the S/D function, and the 16MHz clock output are used in this
case. The application controller does not need to implement these firmware functions and interfaces
but uses the available resources of the TMC8460 instead. Software development is simplified. Other
application parts not covered by the MFCIO block still connect to the microcontroller.