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5.5.4
SMCS332332SpW Routing Examples
When routing, it is recommended that each of the following registers contains a different value: CH1_RT_ADDR,
CH2_RT_ADDR, CH3_RT_ADDR and CHx_ADDR.
Initialization of SMCS332SpW for routing:
register:
- CH1_ADDR
- CH2_ADDR
- CH3_ADDR
- CH1_RT_ADDR
- CH2_RT_ADDR
- CH3_RT_ADDR
- RT_CTRL
Assume that data is incoming on channel 1.
The first byte will be compared with CH1_ADDR, CH2_RT_ADRR and CH3_RT_ADDR and depending on its value,
one of the following actions will be taken.
Case 1) the first byte (address byte) of the received packet is 0xF1:
the packet (excluding address byte F1) will be routed to the internal receive FIFO of channel1.
Case 2) the first byte (address byte) of the received packet is 0x22:
the packet will be routed to the transmit section of channel2.
Case 3) the first byte (address byte) of the received packet is 0x23:
the packet will be routed to the transmit section of channel3.
Case 4) the first byte (address byte) of the received packet is neither 0xF1, 0x22 nor 0x23:
the packet will be routed to the internal receive FIFO of channel1 and error bit5 in CHx_ESR1 will be
set.
In parallel, an interrupt will be raised (if respective bit is set in IMR).
5.6
Header bytes generation
There are two modes to insert header bytes at the beginning of a packet.
A new mode controlled by the header field control bit and the well known SMCS332 mode with routing and checksum
generation.
5.6.1
Header field control bit
For more flexibility for packets routed via a SpaceWire Router, the SMCS332SpW has a header field control bit, D5 in the
register CHx_CNTRL1.
Description: If bit 5 in the register CHx_CNTRL1 is set, the SMCS332SpW will use the first byte of an incoming data to be
transmitted (from COMI or HOCI) as number of bytes which are excluded from checksum (if checksum is enabled). The
allowed range is from 1 to 15. The number byte and the associated header byte(s) defined as header field. The header field
size is minimum 2 and maximum 16 bytes. It is always accessed in blocks of 4 bytes (the first 4, 8, 12 or 16 incoming bytes).
SMCS332SpW
User Manual
value:
= 0xF1
= 0xF2
= 0xF3
= 0x21
= 0x22
= 0x23
= 0x80 (routing enabled)
– 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:
51 of 131
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