buffer mode about str9

[ninesuntj]

Posted on December 25, 2008 at 12:36

buffer mode about str9

[ninesuntj]

Posted on May 17, 2011 at 09:56

there are two work mode about str9 buffer and none buffer,The initial assembler program (init.s)had initialized the mode as buffer mode.The buffered should be defined in at91x_conf.h according with the comment in assembler file. but the buffered was not defined in at91x_conf.h in fact.The document said that hardware had different address in different mode.the program seemed to work normal.why? BTW.st and IAR have two kinds of firmware library.which one is better?

[kais]

Posted on May 17, 2011 at 09:56

Hi,

As you have thought by default at reset, buffered writes are disabled. When enabled (bit 3 of CP15 is set) we have also to select the appropriate address range when writing. As it was implemented the STR9 firmware library enable buffered writes inside the “91x_init.s�. But we still perform a non buffered writes since we are using the non buffered writes address range. For sure this may impose an immediate delay to the CPU, but ensuring data coherency. Hence we kept the choice to user to work or not with buffered writes and this is by uncomment Buffered define in the 91x_conf.h file. Kind regards, Eris.