Error fsmc stm32f4discovery

[sergej]

Posted on July 01, 2012 at 13:32 Hi, everyone. I'm testing on fsmc stm32f407VG. I use the Address / Data multiplexed on databus (MUXEN = 1). 2 modes of testing EXTMOD = 0 and 1. Initialization:

  FSMC_Bank1->BTCR[0] = //FSMC_BCR2_EXTMOD |

                        FSMC_BCR2_WREN   |                         FSMC_BCR2_FACCEN |                         FSMC_BCR2_MWID_0 |                         FSMC_BCR2_MTYP_1 |                         FSMC_BCR2_MUXEN  |                         FSMC_BCR2_MBKEN;                            FSMC_Bank1->BTCR[1]  = (2 << 8) |                 // DATAST = 2                          (1 << 4) |                 // ADDHLD = 1                          (2 << 0);                  // ADDSET = 2     FSMC_Bank1E->BWTR[0] = (2 << 8) |                 // DATAST = 2                          (1 << 4) |                 // ADDHLD = 1                          (2 << 0);                  // ADDSET = 2   If EXTMOD = 0, so good. If EXTMOD = 1, FSMC does not generate NL (NADV) and address (an error when writing and reading). In what may be the problem? This is a bug stm32f407VG?

[zaurozavr]

Posted on July 01, 2012 at 20:25

There is a bug(s) in your code or hw.  Extended address mode assumes you need two ALE strobes, for complex addressing modes. I used to connect external RAM (1MByte) to STM32F4-Discovery board (with my ZP_DSF4 dockstation) in mux mode and all works perfectly. 

[sergej]

Posted on July 04, 2012 at 20:41

I only use stm32f4discovery, the signals look oscilloscope (a bug in the hardware can not be).

I have two programs differ only in one line (bug in the software may not be): FSMC_Bank1-> BTCR [0] = / / FSMC_BCR2_EXTMOD ... - Works MUX FSMC_Bank1-> BTCR [0] = FSMC_BCR2_EXTMOD ... - Does not work MUX (stm32f407 does not give AL and Address on the bus, but the gates are WR, RD and Data these issues).

[zaurozavr]

Posted on July 04, 2012 at 23:59

YOUR software may contain bugs or  improper FSMC initialization. I can assure with right implementation it works fine.

Here you are. My docking station for STM32F4-Discovery:

http://www.zaurosoft.com/images/ZP_DSF4/ZP_DSF4_08.jpg

Timings (not optimal, just for test) for the external RAM in mux mode:

http://www.zaurosoft.com/images/ZP_DSF4/MuxRAM.png

You see the running code as follows:

*(uint16_t *) (Bank1_SRAM1_ADDR + 0x02) = 0xaa;

*(uint16_t *) (Bank1_SRAM1_ADDR + 0x10) = 0x55; *(uint16_t *) (Bank1_SRAM1_ADDR + 0xf0) = 0x18;

*pBuf++ = *(uint16_t*) (Bank1_SRAM1_ADDR + 0x02);

*pBuf++ = *(uint16_t*) (Bank1_SRAM1_ADDR + 0x10); *pBuf++ = *(uint16_t*) (Bank1_SRAM1_ADDR + 0xf0); Due to  16 bit access offsets 0x02, 0x10 and 0xf0  seen as 0x01, 0x08 and 0x78.