Visible to Intel only — GUID: iga1404408556243
Ixiasoft
Visible to Intel only — GUID: iga1404408556243
Ixiasoft
10.2.8. Timing and Fmax
The diagram above shows worst case combinatorial delays throughout the UART IP Core. These estimates are provided by Timing Analyzer under the following condition:
- Device Family: Series V and above
- Avalon® Host connected to Avalon® Agent port of the UART with outputs from the Avalon® Host registered
- RS-232 Serial Interface is exported to FPGA Pin
- Clocks for entire system set at 125 MHz
Based on the conditions above the UART IP has an Fmax value of 125 MHz, with the worst delay being internal register-to-register paths.
The UART has combinatorial logic on both the Input and Output side, with system level implications on the Input side.
The Input side combinatorial logic (with 7ns delay) goes through the Avalon® address decode logic, to the Read data output registers. It is therefore recommended that Hosts connected to the UART IP register their output signals.
The Output side combinatorial logic (with 2ns delay) goes through the RS-232 Serial Output. There should not be any concern on the output side delays though – as it is not a single cycle path. Using the highest clock divider value of 1, the serial output only toggles once every 16 clocks. This naturally gives a 16 clock multi-cycle path on the output side. Furthermore, divider of 1 is an unlikely system, if the UART is clocked at 125 MHz, the resulting baud rate would be 7.81 Mbps.