From: Marcel T. <ma...@te...> - 2003-06-19 10:43:28
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On 2003.06.19 11:20, Gregory Heinrich wrote: > does jtag assume the block is erased while it is in > the programming phase? Yes > i.e. would it work if I just > comment out the block erasing code? If the area is really erased, then yes. Example 1: Assume 0x12345678 data at address 0x0. 1. Programming 0x0 at 0x0 (w/o erasing) causes 0x0 at 0x0. 2. Programming 0xFFFFFFFF at 0x0 (w/o erasing) causes 0x12345678 at 0x0. 3. Programming 0x87654321 at 0x0 (w/o erasing) causes 0x02244220 at 0x0 4. Programming 0x12345678 at 0x0 (w/o erasing) causes 0x12345678 at 0x0 Note: 2 and 3 are bad. Example 2: Assume 0xFFFFFFFF data at address 0x0. 1. Programming 0x0 at 0x0 (w/o erasing) causes 0x0 at 0x0. 2. Programming 0xFFFFFFFF at 0x0 (w/o erasing) causes 0xFFFFFFFF at 0x0. 3. Programming 0x87654321 at 0x0 (w/o erasing) causes 0x87654321 at 0x0 4. Programming 0x12345678 at 0x0 (w/o erasing) causes 0x12345678 at 0x0 > Or is it necessary > to modify the flash programming code so that it performs > erase cycles as well (in which case flash programming > would be much slower)? No. Erase cycle is not required for programming (If you are really sure that the memory area is erased). Regards. -- +-------------------------------------------+ | Marcel Telka e-mail: ma...@te... | | homepage: http://telka.sk/ | | jabber: ma...@ja... | +-------------------------------------------+ |