Microchip SRAM

iemand · 2010-07-02 17:39

Hello all,

I am trying to get a microchip sram 23k256 ic working. I used the winbond flash and microchip sram driver from the object excange.

This is my code: (whitch doesnt work, I only read a 9, 0 or 255 instead of the value it should be)

CON

  _clkmode = xtal1 + pll8x
  _xinfreq = 10_000_000


  'Audio / video output
  L_Audio             = 5                               'Sound (L) output
  R_Audio             = 6                               'Sound (R) output
  COMPOSITE_VIDEO     = 12                              'Video output

  'Controllers
  PS2_toetsenbord_dat = 16                              'Toetsenbord data i/o
  PS2_toetsenbord_clk = 17                              'Toetsenbord clk output
  PS2_muis_dat        = 3                               'Muis data i/o
  PS2_muis_clk        = 4                               'Muis clk output
  gc_controller_1     = 7                               'Gamecube controller 1 data i/o
  gc_controller_2     = 8                               'Gamecube controller 2 data i/o  

  'Intern RAM geheugen
  SRAM_CLK            = 1                               'RAM clk output                  
  SRAM_DIO_DI         = 2                               'RAM data output
  SRAM_DO             = 9                               'RAM data input            
  SRAM_CS1            = 10                              'RAM chipselect 1                     
  SRAM_CS2            = -1'11                           'RAM chipselect 2 (niet gebruikt, zie EXP_P8)

  'SD kaart aansluiting
  SD_CARD             = 24                              'SD Kaart basepin
  spiDO               = 24                              'SD Kaart data input
  spiClk              = 25                              'SD Kaart clk output
  spiDI               = 26                              'SD Kaart data output
  spiCS               = 27                              'SD Kaart chip select

  'Interne eeprom chip voor bootloader                       
  eeprom_clk          = 28                              'EEPROM clk output            
  eeprom_dat          = 29                              'EEPROM data i/o

  'Interne communicatie met PIC chip                                            
  serial_tx           = 30                              'PIC tx output                                          
  serial_rx           = 31                              'PIC rx input

  'Uitbreidingspoort (universeel)
  EXP_P0              = 18
  EXP_P1              = 19
  EXP_P2              = 20
  EXP_P3              = 21
  EXP_P4              = 22
  EXP_P5              = 23
  EXP_P6              = 5
  EXP_P7              = 0 'Nu nog een LED!
  EXP_P8              = 11'Was voor SRAM CS!  

VAR
  byte sram_data, sram_adres, sram_data_check

OBJ

  text : "TV_Text_Half_Height"
  ram      : "ram_flash"


PUB start | i  
  text.start(12,1,0,40,15)
repeat
  enter
    text.ink(5&7)    
    text.str(string("RAM TEST"))
    enter
  text.ink(6&7)    
  text.str(string("v1.4"))

  'text.inkblock(5,2,30,11,1)

  ram.start(-1, SRAM_CLK, SRAM_DIO_DI, SRAM_DO, SRAM_CS1, SRAM_CS2)

  text.ink(2&7)    
  'TEST RAM
  enter
  text.str(string("Writing SRAM... (adr 0 t/m 20)"))
  enter  
  sram_data:= 0
  sram_adres:= 0
  repeat 20
    text.str(string(".")) 
    ram.writeSRAM(@sram_adres, @sram_data, -1)
    sram_data:= sram_data + 2
    sram_adres:= sram_adres + 1
    waitcnt(cnt+1_000_000)    

  enter
  text.str(string("Reading SRAM... (adr 0 t/m 20)"))
  enter
  sram_data:= 9
  sram_data_check:= 0
  sram_adres:= 0 
  repeat 20
    'if sram_adres == 100
    '  quit
    ram.readSRAM(@sram_adres, @sram_data, -1)
    sram_data_check:= sram_data_check + 2   
    sram_adres:= sram_adres + 1
    if not (sram_data == sram_data_check)
      enter
      text.str(string("Error occured on adress "))
      text.dec(sram_adres)
      text.str(string("."))
      enter
      text.str(string("Read: "))
      text.dec(sram_data)
      text.str(string(", should be: "))
      text.dec(sram_data_check)
      text.str(string("."))
      waitcnt(cnt+40_000_000)
    else
      text.str(string("Actie succesvol!"))
      enter
      waitcnt(cnt+40_000_000) 
  waitcnt(cnt+160_000_000)  




PUB cls
  text.out($00)                    
  text.out($01)

PUB enter
  text.str(string($0D))

I think that I am doing something wrong with the variables (@ or not @?).

MagIO2 · 2010-07-02 18:43

I did not have a look in the drivers yet, but this definitely looks wrong:

ram.writeSRAM(@sram_adres,·@sram_data,·-1)

the first parameter is the address in the SRAM and not the address of the sram_adres variable. You really want to give this function the 0 for addressing byte 0 in the SRAM. Whenever you really want to pass the value of a variable, there is no @ involved.

@sram_data seems to be ok.

-1 ? Is that the number of bytes you want to write to the SRAM? Gonna have a look into your archieve to be a better help ....

MagIO2 · 2010-07-02 18:53

If you use a negative count for the read it will not write the content of the SRAM to the memory address you pass it as second parameter, but return it.

So, you have to say:

sram_data := ram.readSRAM( sram_adres, 0 , -1)
or
ram.readSRAM( sram_adres, @sram_data, 1 )

The write works similar
ram.writeSRAM( sram_adres, sram_data, -1)
or
ram.writeSRAM( sram_adres, @sram_data, 1 )

The functions have been designed like that to support direct value passing or passing bigger amount of data by buffers.

Microchip SRAM

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