Datasheet
TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
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Read entire documentation; especially the “Supplemental Directives” on page 224.
MAIN MANUAL
Internal Ramp Generator Units
This section provides information about the arithmetical units of the ramp parameters.
All parameter units are real arithmetical units.
Therefore, it is necessary to set the
CLK_FREQ
register 0x31 to proper [Hz] value,
which is defined by the external clock frequency f
CLK
. Any value between
f
CLK
= 4.2 MHz and 32 MHz can be selected.
Default configuration is 16 MHz.
Velocity values are always defined as pulses per second [pps].
VACTUAL
is given as a 32-bit signed value with no decimal places. The unsigned
velocity values
VSTART
,
VSTOP
, and
VBREAK
consist of 23 digits and 8 decimal places.
VMAX
is a signed value with 24 digits and 8 decimal places.
The maximum velocity
VMAX
is restricted as follows:
Velocity mode: |
VMAX
| ≤ ½ pulse · f
CLK
Positioning mode: |
VMAX
| ≤ ¼ pulse · f
CLK
NOTE:
In case VACTUAL exceeds this limit INCORRECT step pulses at STPOUT output
occur and/or positioning is not executed properly.
Furthermore, VMAX have to be the highest nominal value of all velocity values:
|
VMAX
|
>
max
(VSTART;VSTOP;VBREAK)
The unsigned values
AMAX
,
DMAX
,
ASTART
,
DFINAL,
and
DSTOP
consist of 22 digits
and 2 decimal places.
AACTUAL
shows a 32-bit nondecimal signed value. Acceleration and deceleration units
are defined per default as pulses per second² [pps²].
If higher acceleration/deceleration values are required for short and steep
ramps, do as follows:
Action:
Set
direct_acc_val_en
=1 (
GENERAL_CONF
register 0x00).
Result:
The parameters are defined as velocity value change per clock cycle with 24-bit
unsigned decimal places (MSB =2
-14
). The values are calculated as follows:
AMAX
[pps
2
] =
AMAX
/ 2
37
· f
CLK
2
DMAX
[pps
2
] =
DMAX
/ 2
37
· f
CLK
2
ASTART
[pps
2
] =
ASTART
/ 2
37
· f
CLK
2
DFINAL
[pps
2
] =
DFINAL
/ 2
37
· f
CLK
2
DSTOP
[pps
2
] =
DSTOP
/ 2
37
· f
CLK
2
The maximum acceleration or deceleration values are as follows:
max
(AMAX;DMAX;ASTART;DFINAL;DSTOP)
[pps²]
≤ VMAX
· f
CLK
/ 1024
In case
direct_acc_val_en
= 1, the maximum value is also limited to:
max
(AMAX;DMAX;ASTART;DFINAL;DSTOP) ≤
2
20
Continued on next page.
Clock Frequency
Velocity Value
Units
Acceleration
Value Units