IC-TW14 Datasheet, PDF (26/33 Pages) IC-Haus GmbH – IC-PMX Companion Chip

iC-TW14
iC-PMX Companion Chip
DIAGNOSTIC MODES
Rev A1, Page 26/33
The iC-TW14 provides three diagnostic modes for ana-
lyzing system operation and troubleshooting multiturn
synchronization problems.
SSI Test Mode
SSI test mode is used to test the SSI multiturn interface
by supplying known static position data which can be
verified in the external singleturn absolute sensor. To
use SSI test mode, first enter the least significant word
of the desired test position to DATA.0 and the most sig-
nificant word to DATA.1. See Data Registers on page
20 for more information.
For example, to test the SSI multiturn interface using
the 32-bit multiturn data 0x76543210, set
DATA.0 = 0x3210
DATA.1 = 0x7654
Initiate SSI test mode using the SSI_TEST command
(40). See MODE/CMD on page 19 for more information.
The external singleturn absolute sensor will then clock
in as many of these multiturn bits as it is configured to
use starting with the most significant bit of DATA.1.
Because the SSI multiturn protocol requires a trailing
zero after all bits are sent, it is important that the test
position in DATA.0 and DATA.1 provide a zero bit at the
proper position. For example, if the external singleturn
absolute sensor is programmed to require 16 multiturn
bits and 1 sync bit, the 18^th bit of the SSI data packet
(bit 14 of DATA.0 in this example) must be zero, as
shown in Figure 6.
SSI Test
Data
DATA.1
DATA.0
76543210
01110110010101000011001000010000
SSI Data 0 1 1 1 0 1 1 0 0 1 0 1 0 1 0 0 0 0
Bit 18 must be 0
16 Multiturn Bits
1 Sync Bit
Figure 6: SSI Test Example
Care must be taken to ensure that this requirement is
fulfilled, otherwise the SSI multiturn communication will
fail.
Note that SSI test mode sets STATUS.STOP (see STA-
TUS on page 14 for more information). To end SSI
test mode and clear STATUS.STOP, re-synchronize the
iC-TW14 to the iC-PMX using the RESYNC command
(8).