TMC428_06 Datasheet, PDF (14/58 Pages) List of Unclassifed Manufacturers – Intelligent Triple Stepper Motor Controller with Serial Peripheral Interfaces

TMC428 DATASHEET (v. 2.02 / April 26^th, 2006)
14
7 Address Space Partitions
The address space is partitioned in different ranges. Each of the up to three stepper motors has a set
of registers individually assigned to it, arranged within a contiguous address space. An additional set of
registers within the address space holds some global parameters common for all stepper motors. One
dedicated global parameter register is essential for the configuration of the serial four wire stepper
motor driver interface. One half of the on-chip RAM address space holds the configuration parameters
for the stepper motor driver chain. The other half of the on-chip RAM address space is provided to
store a micro step table if required. The first seven datagram bits (sdi_c_bit#31 and sdi_c_bit#30 ...
sdi_c_bit#25, respectively RRS and ADDRESS) address the whole address space of the TMC428.
address ranges (incl. RRS)
%000 0000 . . . %000 1111
%001 0000 . . . %001 1111
%010 0000 . . . %010 1111
%011 0000 . . . %011 1110
%011 1111
%100 0000 . . . %101 1111
%110 0000 . . . %111 1111
assignment
16 registers for stepper motor #1
16 registers for stepper motor #2
16 registers for stepper motor #3
15 common registers
1 global parameter register
32 addresses of 2x6 bit for driver chain configuration
32 addresses of 2x6 bit for microstep table
registers
with up to
24 bits
RAM
128x6 bit
Table 7-1: TMC428 address space partitions
The stepper motors are controlled directly by writing motion parameters into associated registers. Only
one register write access is necessary to change a target motion parameter. E.g. to change the target
position of one stepper motor, the microcontroller has to send only one 32 bit datagram to the
TMC428. The same is true for changing a target velocity. Some parameters are packed together in a
single data word at a single address. Those parameters– initialized once and unchanged during
operation –have to be changed commonly. Access to on-chip RAM addresses concern two successive
RAM addresses. So, always two data words are modified with each write access to the on-chip RAM.
Once initialized after power-up, the content of the RAM is usually left unchanged.
7.1 Read and Write
Read and write access is selected by the RW bit (sdi_c_bit#24) of the datagram sent from the µC to
the TMC428. The on-chip configuration RAM and the registers are writeable with read-back option.
Some addresses are read-only. Write access (RW=0) to some of those read-only registers triggers
additional functions, explained in detail later.
7.2 Register Set
The register address mapping is given in Table 7-2 on page 15. These registers are initialized internally
during power-up. During power-up initialization, the TMC428 sends no datagrams to the stepper motor
driver chain.
Note: The RAM has to be initialized before writing target parameters to the register set.
7.3 RAM Area
The RAM address mapping is given in Table 10-1 page 35. The on-chip RAM is NOT initialized
internally during power-up. This has to be done by the microcontroller before operation.
Note: There are unused addresses within the address space of the TMC428. Access to these
addresses has no effect. How ever, access should be avoided, because this address space may be
used for future devices.
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG