12. Serial RapidIO Registers > RapidIO Physical Layer Registers
273
Tsi578 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
12.6.4
RapidIO Serial Port x Link Maintenance Request CSR
According to the
RapidIO Interconnect Specification (Revision 1.3)
only one link maintenance request
can be outstanding at a time. However, the
Tsi578
can be instructed to produce four consecutive link
maintenance requests in order to quickly re-establish a link.
Multiple link maintenance request symbols are generated by the CMD field in the RapidIO Serial Port
x Link Maintenance Request CSR. An external device can write to this register and generate a
link-request control symbol on the corresponding RapidIO port. A read to this register returns the last
value written.
The control symbols generated by this register are encoded as: ackIDbuf_
lCMD.
If the
Tsi578
sends its own link maintenance request, and if that request is outstanding and the CMD
field is written to, then the register write is ignored. If this register is written twice in rapid succession,
it could cause a protocol violation.
If the RapidIO Serial Port x Link Maintenance Response CSR does not indicate that the link-request is
complete, software must ensure that a period of time equal to the Port Link Timeout period, controlled
by the RapidIO Switch Port Link Time Out Control CSR, has passed before attempting another link
maintenance request to avoid protocol violations.
Register name: SP{0..15}_LM_REQ
Reset value: 0x0000_0000
Register offset: 140, 160, 180, 1A0, 1C0, 1E0, 200, 220,
240, 260, 280, 2A0, 2C0, 2E0, 300, 320
Bits
0
1
2
3
4
5
6
7
00:07
Reserved
08:15
Reserved
16:23
Reserved
24:31
Reserved
CMD
Bits
Name
Description
Type
Reset
Value
0:28
Reserved
N/A
R
0
29:31
CMD
Command
Command to be sent in the link-request control symbol. If read,
this field returns the last written value.
011 = Reset. Writing this value causes the device to send four
consecutive reset control symbols.
100 = Input-status
Other values are reserved, but the Tsi578 sends a control symbol
with the requested value.
R/W
0