fpga - Massachusetts Institute of Technology Department of...

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Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.111 — Introductory Digital Systems Laboratory FPGA Module D. E. Troxel 1 (April 8, 2002) (Revised: January 23, 2004) 1 WARNING - BURN OUT A number of students have burned out FPGAs. The following describes the probable cause. This has not been con±rmed by experiment. I really don’t want to perform this experiment. The FPGAs that have been fried are the 10K70 (the right hand one). The 10K70 is surface mounted and it is expensive to replace. In addition, the pc board is often damaged in trying to replace the 10K70. We have a limited number of pc boards! Altera states that unused pins MUST be unconnected. This is not possible for the pins connected to the AD bus (see below). In particular, you must not have the switches driving the AD bus unless the Flex devices are tristated for all of the AD bus pins that are driven by the switches. Remove the jumper used to enable the switches by grounding NUSW. If in doubt, read the handout that describes the kit wiring. If you can’t ±nd it then look for it on the web page. All of these AD bus pins must be used as inputs, outputs, or speci±cally tri-stated. In addition, all pins that are connected to a 50 pin connector (see below) should be used as inputs, outputs, or speci±cally tri-stated. Unfortunately, there is no easy way to tristate unused pins. Altera literature says that unused pins are grounded and MUST be unconnected. Unused pins must be speci±cally listed in the top level entity and speci±cally tri-stated. See the example ±les tristate.acf and tristate.vhd Please use the 10K10 (on the left) until you are familiar with the use and programming procedures. This device is in a socket and at least we can replace it if you burn it out. 2 FPGA Module The FPGA module consists of two of Altera’s FLEX 10K PLDs (one FLEX 10K10 and one FLEX 10K70) which can be accessed through the lab kit’s NuBus interface and 50-pin ribbon cable connectors. The state of the NuBus interconnects can be continuously displayed on the lab kit’s hex leds by connecting jumpers /LHEX and /HHEX to /CLK (or any other clock). Also, the Proto strip connection labeled NUHEX must be grounded.
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fpga - Massachusetts Institute of Technology Department of...

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