We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.
In the following code fragment, QDATA code NtscROM[CSR_ROM_SIZE] = { // Philips configuration ROM for NTSC 0x0404E525, // Bus Info Length, CRC length, CRC 0x31333934, // "1394" 0xE0644000, // node capabilities 0x00603700, // node_vendor_id:0x006037 Philips Semiconductors, chip_id_hi 0x4E545343, // chip_id_low I need my running application to over-write some of the entries in the compiled-in "ROM" table. Philips has some assembly samples (See Philips Application Note AN461) but I don't know how to fit this together with my 'C' code. Anybody know how to do this? Thanks, jmh
The RD+ has a built-in API to flash code (see datasheet of RD+). The functions of this API are not compatible with the calling conventions of C51, so you have to write some wrapper functions in assembly, to move parameters to the correct registers. Your table has to be put into a separate block of the flash memory. The RD+ is divided in four of such blocks. By the way, I've heard that the RD+ will be obsolete next year, so better look for the RD2.
>>Your table has to be put into a separate block of the flash memory. The RD+ is divided in four of such blocks. When my wrapper code calls the flash writing API, that code is actually executing in the BOOTROM. So it would seem that all the flash memory blocks would be available for writing; the location of the calling code would be irrelevant. Is this not so? jmh
Yes, the location of the calling code is not relevant. But if you place the calling code in the same block as your config array, you have to write your array, but also the calling code and everything else in that block. (Because the entire block has to be erased first.)
Here you have some examples for 89C51Rx2. It could give you some ideas to don't write all flash for every variable you write. I don't kwnow if the wrapper functions will work on your 89C51RD+ but give it a look for using variables in flash. http://www.esacademy.com/faq/progs/flash.htm file: rx2fv_lib.zip