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Altera_Forum
Honored Contributor I
801 Views

De2_tv

in example of DE2_TV. Mean of parameter in module Sdram control: 

//////////// 100 MHz /////////////// 

//************************************************************************* 

parameter INIT_PER = 24000; 

parameter REF_PER = 1024; 

parameter SC_CL = 3; 

parameter SC_RCD = 3; 

parameter SC_RRD = 7; 

parameter SC_PM = 1; 

parameter SC_BL = 1; 

parameter SDR_BL = (SC_PM == 1)? 3'b111 : 

(SC_BL == 1)? 3'b000 : 

(SC_BL == 2)? 3'b001 : 

(SC_BL == 4)? 3'b010 : 

3'b011 ; 

parameter SDR_BT = 1'b0; // Sequential 

// 1'b1: // Interteave 

parameter SDR_CL = (SC_CL == 2)? 3'b10: 

3'b11; 

//***************************************************************************************** 

please help me
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Altera_Forum
Honored Contributor I
67 Views

nobody help me!! :(

Altera_Forum
Honored Contributor I
67 Views

SC_CL = CAS Latency 

SC_RCD = Row Address to Column Address delay  

SC_RRD = Row to Row activation delay 

SC_PM = Page Mode 

SC_BL = Burst Length 

 

SDR_BT = Burst Type (sequential or Interleaved)
Altera_Forum
Honored Contributor I
67 Views

Also, the INIT_PER is initialization period. During initialization we first wait for 100us and then apply sequence of commands to initialize the SDRAM. The INIT_PER helps to keep track of where we are in the process and its value is decoded to decide which command to apply. 

 

The REF_PER is counter used to decide when to issue auto-refresh command to the SDRAM. 

 

For anyone requiring details, you must first understand the basic of an SDRAM. There are application notes that do that quite well and also carefully read the datasheet for the IS42S16320. 

 

The following are a good start: 

An introduction to SDRAM and memory controllers (Philips) 

SDR SDRAM Controller (Reference Design RD1174) (Lattice Semiconductor) 

SDR SDRAM Controller (Reference Design RD1010) (Lattice Semiconductor) 

IS42S16320 Datasheet 

 

Enjoy
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