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What are the worst-case values for the AS mode parameters for EP4CGX22 + EPCS4 bundle?
I mean - everything besides configuration time to transfer bitstream.
Knowing it I can calculate how many bits of configuration file will go through the rest of 100 ms window and only after this I can see - will my project squeeze in.
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Starting with the Cyclone IV Handbook (CYIV-5V1-1.9)
http://www.altera.com/literature/lit-cyclone-iv.jsp p172 of the PDF, Table 8–3, has the MSEL options for the GX devices - you would select AS Fast POR mode.
p450, Table 1–3, indicates that the power supply ramp time must be tRAMP < 3ms for fast POR mode.
p176, Table 8–6, has the "AS DCLK Output Frequency", showing the worst-case is 20MHz.
p473, Table 1–29, shows that the typical AS frequency is 33MHz.
p169, Table 8-2, has the configuration file sizes. The EP4CGX22 has a configuration bit-length of 7,600,040
At a DCLK of 20MHz, the configuration bit-stream time is 7,600,040/20MHz = 380ms.
So there's no need to add in the POR and configuration control signal delays, as the 100ms time is completely blown out by the worst-case configuration time.
Contrast this to using PS mode or FPP mode;
p200, Table 8–12, fDCLK(max) = 66MHz or 133MHz depending on the device.
If you want the bit-stream to configure in say 80ms, then fDCLK for PS mode must be 7,600,040/80ms = 95MHz. This is possible if you are using a device that can operate at up to 133MHz.
A more conservative solution is to use FPP mode.
p208, Table 8–13, fDCLK(max) = 66MHz or 133MHz depending on the device, i.e., the same as PS mode, but this time you transfer 8-bits of data for every DCLK period, so ... fDCLK for FPP mode must be 7,600,040/(8 x 80ms) = 95MHz/8 = 12MHz.
A MAX II CPLD plus a QSPI flash can easily operate at 12MHz, this means with FPP mode, there is no problem meeting the power-on requirement.
But you have to add two devices - is that expensive? No.
EPCS4 $13
http://www.digikey.com/product-detail/en/epcs4si8/544-1243-5-nd/703950 MAX II CPLD EPM240M100C5N $6
http://www.digikey.com/product-detail/en/epm240m100c5n/544-1706-nd/1136022 Micron/Numonyx N25Q Quad-SPI Flash
http://www.micron.com/products/nor-flash/serial-nor-flash a 16Mbit device should be good, eg., N25Q016A11ESC40F, but they're not in stock, so lets go for a 128Mbit part
$3.07
http://www.digikey.com/product-detail/en/n25q128a13ese40e/557-1562-nd/3874288 So you see, a MAX II plus QSPI flash is *cheaper* than an Altera EPCS4.
Cheers,
Dave
Honored Contributor
