Datasheet

TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
154/230
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Read entire documentation; especially the “Supplemental Directives” on page 224.
 MAIN MANUAL 
If safe transmission must be determined, it is possible to send a second request so
that the encoder repeats the same encoder data. Therefore, a second interval
SSI_WTIME must be defined.
i According to SSI standard, select an interval that is shorter than 19 µs.
In order to enable multicycle requests, do as follows:
Action:
 Set ssi_multi_cycle_data =1 ( ENC_IN_CONF register 0x07).
 Set proper SSI_WTIME (register 0x57) in internal clk cycles.
Result:
After a data request – when all clock cycles have been emitted – the serial clock
remains idle for SSI_WTIME clock cycles. Afterwards, the second request is
automatically initiated to receive the same encoder data. If the second encoder data
differs from the first one, error flag MULTI_CYCLE_FAIL (register 0x0F) and error
event SER_ENC_DATA_FAIL (register 0x0E) is generated.
After the second data request, the next interval lasts SER_PTIME clock cycles to
request new encoder data.
Several but not all SSI encoders emit angle data, which is gray-encoded. TMC4361A
is able to decode this data automatically.
In order to enable gray-encoded angle data, do as follows:
Action:
 Set ssi_gray_code_en =1 ( ENC_IN_CONF register 0x07).
Result:
Encoder data is recognized as gray-encoded and thus also decoded accordingly.
Enabling
Multicycle
SSI request
Gray-encoded
SSI Data
Streams