Intel® Quartus® Prime Software
Intel® Quartus® Prime Design Software, Design Entry, Synthesis, Simulation, Verification, Timing Analysis, System Design (Platform Designer, formerly Qsys)
15682 Discussions

Setup ALTGX_RECONFIG instances for two ALTGX instances on the same transceiver block

Honored Contributor II

How to setup and connect one ALTGX_RECONFIG instances for two ALTGX instances on the same transceiver-block ? 



* Quartus 14.1 

* FPGA: Cyclone IV GX EP4CGX15F14C6N 


Each ALTGX instances support one channel as follow: 

1. PCIe - generated by Qsys. 

There is a bug in Quartus that does not allow to configure "starting channel number" so as I understand, it's fixed internally to 0. 

2. Basic - generated by ALTGX MegaWizard Plug-In Manager. 

The "starting channel number" was set to the next value that is '4'. 


Each ALTGX instances has reconfig_fromgxb[4..0] output and reconfig_togxb[3..0] input. reconfig_togxb[3..0] is connect in paralell to ALTGX_RECONFIG. 


At ALTGX_RECONFIG instance for "What is the number of channels controlled by the reconfig controller?" I set to 2 since there are two channels (PCIe and Basic). 

ALTGX_RECONFIG instances has reconfig_fromgxb[4..0] input and reconfig_togxb[3..0] output. 


From Cyclone IV Device Handbook, Dynamic Reconfiguration Controller Port List there is some hint how to connect multiply ALTGX instances to a single ALTGX_RECONFIG instance. 

According to the hint, 

* connect the reconfig_fromgxb[4..0] of altgx instance 1 to the reconfig_fromgxb[4..0] of the altgx_reconfig instance. 

connect the reconfig_fromgxb[] port of the next altgx instance to the next available bits of the altgx_reconfig instance, and so on. 

* connect the reconfig_fromgxb port of the altgx instance, which has the highest what is the starting channel number? option, to the msb of the reconfig_fromgxb port of the altgx_reconfig instance. 


therefore I connected as follow: 

* reconfig_fromgxb[4..0] output from PCIe instances to ALTGX_RECONFIG instance reconfig_fromgxb[4..0] input. 

* reconfig_fromgxb[4..0] output from basic instances to nothing since there is no other ALTGX_RECONFIG instance reconfig_fromgxb[4..0] input left to connect. 


When compile I get this error: 

error (15629): atom "address_pres_reg[0]~3" is dependent on unconnected input ports 


I noticed this link "" discuss about this error but it didn't much help. 


Any idea ?
0 Kudos
2 Replies
Honored Contributor II



Did you try the suggestion given in link? 

to use the latest version of quartus. 


Let me know if you need any further assistance. 


Best Regards, 

Anand Raj Shankar 

(This message was posted on behalf of Intel Corporation)
Honored Contributor II



Tested with Quartus 13 and 17.1, on both of them the issue is fixed and there is no such error.  



I had to set to 8 "what is the number of channels controlled by the reconfig controller?" so ALTGX_RECONFIG instances will have reconfig_fromgxb[9..0] although I have only two channels (PCIe and Basic).  

why ? 

It would be much simpler to understand and connect if GX reconfig port would be a seperate ALT instance take care the all PHY channels and not spread between ALTGX instances.