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5 SMCS332SpW Modes
This section describes the organization of data passing through the HOCI and COMI ports on the SMCS332SpW, the
procedure used to arbitrate between two SMCS332SpW on the COMI port, control by link, the SMCS332SpW routing
capability., the time code interface and the version control register.
5.1
HOCI Data Transfer
Big/Little endian selection of the HOCI is done using a special pin (HOSTBIGE) of the SMCS332SpW. By connecting this
pin to either Vcc or GND the HOCI is configured to be in little or big endian mode as follows:
When Signal HOSTBIGE = '0' (GND), the HOCI data port is in little endian mode.
When Signal HOSTBIGE = '1' (Vcc), the HOCI data port is in big endian mode.
Little endian mode selected:
-
8 bit data port (default after reset)
- register byte 0 is connected with pin HDATA7 - HDATA0
-
16 bit data port
- register byte 0 is connected with pin HDATA7 - HDATA0
- register byte 1 is connected with pin HDATA15 - HDATA8
-
32 bit data port
- register byte 0 is connected with pin HDATA7 - HDATA0
- register byte 1 is connected with pin HDATA15 - HDATA8
- register byte 2 is connected with pin HDATA23 - HDATA16
- register byte 3 is connected with pin HDATA31 - HDATA24
Big endian mode selected:
-
8 bit data port (default after reset)
- register byte 0 is connected with pin HDATA31 - HDATA24
-
16 bit data port
- register byte 0 is connected with pin HDATA31 - HDATA24
- register byte 1 is connected with pin HDATA23 - HDATA16
-
32 bit data port
- register byte 0 is connected with pin HDATA31 - HDATA24
- register byte 1 is connected with pin HDATA23 - HDATA16
- register byte 2 is connected with pin HDATA15 - HDATA8
- register byte 3 is connected with pin HDATA7 - HDATA0
The registers of the SMCS332SpW are 1, 2 or 4 Bytes wide. That means, if the HOCI data port is in 8 bit mode, 4 read or
write accesses are necessary to access a 4 Byte register (e. g. the interrupt mask register). In 16/32 bit mode the data bits 31 -
8 are '0' if an 8 bit register is read.
SMCS332SpW
User Manual
– All Rights Reserved – Copyright per DIN 34 –
EADS Astrium GmbH, ASE2
Doc No: SMCS_ASTD_UM_100
Issue:
1.4
Updated: 9-Sep-2006
Page:
44 of 131
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