[SOLVED] 7i90 25Mhz oscillator on Dev-Board

Currently i'm trying to adapt the 7i90 firmware on a xc6slx16 FT(G)256 Dev-Board
So i already changed:

• The matching pinout in the .ucf file
• The package type in the.xise file
• The pincount and fpga size in the i90_x9card file

The thing that is not quite clear to me is : Where and which clock settings to changed, since the board has a 25Mhz oscillator instead the 50Mhz on the original board. Which clocks and/or setting should be changed, and what are they used for?
I found the following:

i90_x9card.vhd > IDROMConst.vhd

• constant ClockHigh90: integer := 200000000;
• constant ClockMed90: integer := 100000000;
• constant ClockLow90: integer := 100000000

7i90spi.ucf

• TIMESPEC "TS_CLK" = PERIOD "CLK" 19.9 ns HIGH 50 %;
• TIMESPEC "TS_COM_SPICLK" = PERIOD "COM_SPICLK" 9 ns HIGH 50 %;

TopGCSPIHostMot2.vhd

• signal fclk : std_logic;
  signal clkfx0: std_logic;
  signal clk0_0: std_logic;
  signal clklow : std_logic;
  signal clkfx1: std_logic;
  signal clk0_1: std_logic;


• clklow => clklow, -- I/O clock
  clkmed => clklow, -- Processor clock
  clkhigh => fclk, -- PWM clock


• ClockMultH : DCM
  generic map (
  CLKDV_DIVIDE => 2.0,
  CLKFX_DIVIDE => 2,
  CLKFX_MULTIPLY => 8, -- 8 FOR 200 MHz
  CLKIN_DIVIDE_BY_2 => FALSE,
  CLKIN_PERIOD => 20.0,


• ClockMultM : DCM
  generic map (
  CLKDV_DIVIDE => 2.0,
  CLKFX_DIVIDE => 2,
  CLKFX_MULTIPLY => 4, -- 4 FOR 100 MHz
  CLKIN_DIVIDE_BY_2 => FALSE,
  CLKIN_PERIOD => 20.0,


• asimplspi: entity work.simplespi8 -- configuration serial EEPROM access SPI port
  generic map
  (
  buswidth => 8,
  div => 7, -- for divide by 8 -- 12.5 MHz

Should only the clk periods be changed from 20 to 40, or should the clk dividers also be adapted?
Thanks in advance,

You would change

ClockMultH CLKFX_MULTIPLY to 16
ClockMultM CLKFX_MULTIPLY to 8

TIMESPEC "TS_CLK" = PERIOD "CLK" 39.8 ns HIGH 50 %;

and both clock periods to 40

Thanks ,

With those setting i can confirm the RV901T Led Receiving board as working having 72 5v outputs.

Hello pauluzs,

pauluzs wrote:

Thanks ,

With those setting i can confirm the RV901T Led Receiving board as working having 72 5v outputs.

Could you kindly share the final changes you did for the hostmot2 xilinx sources or take a look at my github.com/golyakoff/hostmot2-rv901t-7i90/commits/master ? I tried to follow your instruction but get stucked...

It builds but SPI I see garbage on the SPI MISO: here are the details... forum.linuxcnc.org/38-general-linuxcnc-q...king?start=10#296830.

Thank you in advance!