What is In-System Device Programming (ISP)
ISP refers to programming or configuring programmable hardware devices such as Programmable Logic Devices (PLDs), Programmable Array Logic (PALs), and Complex Programmable Logic Devices (CPLDs)
after they have been assembled on the printed circuit board. These are non-volatile devices which means that once they are configured, they will not lose their configuration with cycling of
power. Traditional manufacturing methods rely on programming ISP devices before assembling them onto the printed circuit board. Serious limitations result from adopting this method; With the
increasing variety of parts and programming data, the logistic costs of ensuring that correct parts having the right programs are assembled to the printed circuit board rise dramatically.
Also, based on traditional programming and manufacturing methods, if the wrong program is dropped into a part and assembled to the printed circuit baord, the whole part must be physically
replaced to rectify the problem. Finally, since engineering changes will involve parts removal, the process of implementing the changes may diminish product quality, and the associated costs
can be quite high. ISP offers complete and total flexibility in dealing with these problems because it relies on assembling a generic part first and dropping the program into the part after
it has been assembled.
As time-to-market pressures increase, design engineers look for ways to increase the pace of development. ISP devices can help to accelerate development times, simplify manufacturing flows,
lower inventory costs, and improve testability. Implementing the boundary scan (JTAG) port has become a standard approach within the industry to programe most PLDs, CPLDs, etc., and suppliers
of these devices are loyal to a policy of supporting the IEEE 1149.1 protocol.
Using boundary scan (JTAG) at the board level - which must be designed correctly - also allows manufacturing engineers to use in-circuit testers for programming these devices. Usually the
manufacturing process is simplified and improved by eliminating a separate programming station and reducing the number of manufacturing steps.
What is On-board programming (OBP)
OBP refers to the programming of target memory on a board through boundary scan compliant devices on the board. The target memory (flash) to be programmed is itself not IEEE 1149.1 compliant.
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