IDT Programming the Device
Revision 1.5
Integrated Device Technology, Inc.
CPS-16/12/8 User Manual
8 - 2
July 10, 2012
As the response to a Maintenance Request Packet, a Maintenance Response Packet is created using the
format below with the hop_count field set to 0xFF. Responses are sent via the port on which the Mainte-
nance Packet was received.
In the response packet, the following fields are turned around from the request packet as defined below:
1) rsvd
2) CRF: The CPS copies this from the request maintenance packet, but otherwise will ignore the
received value.
3) tt
4) ftype
5) targetTID(srcTID in the request packet)
Other fields are generated as follows:
1) AckID is generated as defined in sRIO at the PHY link level
2) the prio field is increased by one compared to the request packet. If the request priority was 3
then the response will be kept at priority 3
3) destinationID uses the value of the request packet’s sourceID field
4) sourceID uses the value of the request packet’s destinationID field
5) transaction is set to the correct response type as defined in the RIO specification
6) status is always set to 0b0000
7) hop_count is set to 0xFF
8) read data as requested is provided in response packets
The device support the ability to process all self destined (i.e. with a hop count of 0) maintenance packets
(without dropping them) as long as they are received with a spacing (time between packets -- SOP to SOP)
of 32 ns.
8.1.2 I2C access
Please refer to I2C chapter.
8.1.3 JTAG access
Please refer to JTAG chapter.
Table 8.2 RIO Defined Maintenance Response Packet generated by CPS
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
AckID
rsvd
CRF
Prio
tt
ftype = 0b1000
destination ID
source ID
ttype
rdsize/wrtsize
Target Transaction ID (targetTID)
Hop_Count = 0xFF
Config_Offset [20:13]
Config_Offset [12:0]
W
0b00
Data
Data......................................................................................................Data
Data
CRC