Critical Issue
If you attempt to generate the ALTGXB megafunction from a command line using qmegawiz -silentgeneration fails with messages similar to the following:
Error: The GXB PLL 'CMU' parameter 'input_clock_frequency'
is set to an illegal value of '155.52 MHz'. The value is illegal
when the device speed grade is '4', the parameter 'base_data_rate'
is set to '2967.0 Mbps', and the parameter 'Pll Type' is set to
'CMU' on atom 'test_alt4gxb_t3t6:test_alt4gxb_t3t6_component|tx_pll_alt0'
Error: The 'GXB PLL' parameter 'm' is set to an illegal
value of '1'. The reference clock frequency to the PLL PFD (phase-frequency
detector), which is input_clock_frequency ('155.52 MHz') \ n ('1'),
must be the same as the feedback frequency to the PLL PFD, which
is base_data_rate ('2967.0 Mbps') \ 2 \ m on atom 'test_alt4gxb_t3t6:test_alt4gxb_t3t6_component|tx_pll_alt0'
Error: The 'GXB PLL' parameter 'n' is set to an illegal
value of '1' on atom 'test_alt4gxb_t3t6:test_alt4gxb_t3t6_component|tx_pll_alt0'.
The value of n is restricted based on the min and max reference
clocks to the PLL PFD (phase-frequency detector) for the speed grade
of 4 and the specific Pll Type of 'CMU'. For non-basic protocol
configurations, the value of N is fixed.
Use the MegaWizard Plug-In Manager GUI to configure and generate your ALTGXB megafunction.