iC-MD RS-422 QUADRATURE
ENCODER RECEIVER/COUNTER WITH SPI AND BiSS
Rev A1, Page 11/23
48 BIT COUNTER
iC-MD has a 48 bit counter configurable as from one EXCH = 0 and INVZ = 0. All other configurations are
up to three counters with bit lengths from 16 to 48 bit. also possible.
Table 16 shows all the possible counters configuration.
CFGZ
Code
00
Addr. 0x01; bit (4:3)
Function:
00
The counter configuration is given by the registers
CNTCFG as shown in table 16. If it is configured with
more than one counter, the input stage must be set to
TTL (table 12).
Z active: when A = 1 B = 1
Z active: when A = 1 B = 0
Z active: when A = 0 B = 1
Z active: when A = 0 B = 0
01
10
11
CNTCFG
Code
000
Addr. 0x00; bit (2:0)
Counter Configuration
000
Table 17: Index Signal Configuration
1x24 bit counter
2x24 bit counter
1x48 bit counter
1x32 bit counter
1x32 bit + 1x16 bit counter
1x16 bit counter
2x16 bit counter
3x16 bit counter
001
It can also be deactivated the clearing of counter by
the index signal with the configuration bit CBZ ( table
18 ).
010
100
101
011
The CBZ configuration is only applicable after the sec-
ond index pulse after power-on or the activation of
ZCEN (table 23), because after it, the iC-MD will reset
the counter value by the firsts two index pulse, inde-
pendently of the CBZ configuration, in order to have
the AB Counter value referenced to the second index
pulse. By default, CBZ is set to 0, also the counters
are not reset to 0 by the index signal. But the firsts two
Index pulse always reset the counters.
110
111
Table 16: Counter Length
The 48 bit register of the AB counter is also used as
"SPI data channel" for data exchanging between SPI
and BiSS interface, for that purpose the bit CH0SEL
(table 45) must be set to 1. When CH0SEL = 1, the
counting function for all the counters is deactivated.
CBZ
Code
x1
Addr. 0x01; bit (6:5)
Function
00
CNT0 cleared by Z0 signal
CNT1 cleared by Z1 signal
1x
Index Signal (Z)
In default operation configuration, the index signal (Z)
is active when A = B = 1, as shown in table 17 with
Table 18: Clear by Z
ICHAUS [ IC-HAUS GMBH ]
