AnsweredAssumed Answered

External Addressing question

Question asked by bamford.konrad on Nov 26, 2012
Latest reply on Nov 26, 2012 by bamford.konrad
I am using a STM32F4 FSMC to address external 16-bit SRAM on a custom board.  Everything is OK.
I want to connect an external FPGA and I'm not so clear about the actual addressing.
Please correct me if I'm being stupid, the MCU is 32bit, but the internal AHB address bus is bytewise.  The external address bus is 16-bit, so A0 addresses 2 x 16-bit locations.
Therefore to access say
0x00000004 & 0x00000005 A0=1 A1=1 A2=0
0x00000000 & 0x00000001 A0=0 A1=0 A2=0
0x00000002 & 0x00000003 A0=1 A1=0 A2=0

Or is it bytewise
0x00000000 A0=0 A1=0 A2=0
0x00000001 A0=1 A1=0 A2=0

Or is it 32-bit wide as the 16-bit words are read in in 2 cycles
0x00000000 A0=0 A1=0 A2=0
0x00000004 A0=1 A1=0 A2=0




Outcomes