Making ROMS

Note that you will need to set the device type and split multiple (if any) before you start the download. A split multiple is necessary if the Target board requires more than one ROM as a minimum configuration.

Note that if your board requires more than one ROM as a minimum configuration and is also using the little endian byte ordering, the ROMs will need to be inserted in the reverse order to that used by a big endian processor. For example, if a board has sockets A, and B, and for big endian, device 1 from the programmer is inserted in socket A, and device 2 in socket 2. The reverse will be true for little endian, ie. device 1 will be inserted in socket B, and device 2 in socket A.

Then set the Programmer's record type to Motorola S-records. For some toolsets, you will also need to specify an offset on the PROM programmer. The offset is required because some toolsets produce S-records that start at a non-zero address, whereas most PROM programmers expect the S-records to start at zero. The following table shows the offsets required for the various MIPS toolsets.

You must make sure that the PROM you are using is large enough to hold the program. Unfortunately, most PROM Programmers will not warn you if your program is too large. You should be suspicious if the PROM Programmer reports that the number of bytes downloaded is exactly the same size as your PROM; this generally means that some data is being omitted. Note that you cannot simply look at the address in the last record of the S-record file, because some toolsets do not emit the S-records in order.

If you don't have a PROM programmer, I can personally recommend the emp20 programmer from Needham's Electronics. It is inexpensive and connects to the parallel port on a PC.