I'm trying to access external devices on a XC161. A0-A19 are active. So are CS0-CS4. ADDRSEL4 is set to 0x0400 (start at 40000h, size 4k) Writing to 0x40000 works but CS0 is activated not CS4 ??? I have no experience with this family, so I must be doing something silly... Startup file was generated by DAVE, but checked out to be correct. Writing is done by use of a pointer. Is there an other/more direct way of accessing external memory/device? Frank
I'm not sure why CS4 is not going active but I do know that CS0 is the "default" chip select. This means that if there is a memory access that does not fall within the range of the other chip selects, CS0 will go active. You can use the definitions in absacc.h of the keil/c166/inc directory for direct access to external memory. -Walt