SDRAM full page burst mode stoping

Question

I'm working on an SDRAM controller to handle a frame buffer. I want to know, Is it possible to terminate a full-page burst mode by a PRECHARGE command? Although a STOP command will do it, I want to close a row by a single command (only a PRECHARGE command).

Answer 1

According to JEDEC documents (JEDEC Standard No. 21--C Page 3.11.5.1 -- 18):

A full page burst sequence can be terminated by a BST (burst stop command which is also an optional feature), a PRE (Precharge Command), a PREALL (Precharge all banks command) or another full page burst read or write command.

• BST is an optional feature on SDRAMs/SGRAMs. BST will terminate the burst sequence, but will not cause the device to precharge the accessed bank (i.e., the bank remains active). Additional read or write commands can be executed while the bank is active. A subsequent PRE command is used to return the selected bank to the idle state (row precharge time must be satisfied). A subsequent PREALL command is used to return all banks to the idle state (row precharge time must be satisfied).
• PRE will terminate the burst sequence and will initiate a precharge operation which returns the selected bank to the idle state (row precharge time must be satisfied).
• PREALL will terminate the burst sequence and will initiate a precharge operation which returns all banks to the idle state (row precharge time must be satisfied)
• Read/write interrupt of the full page burst will cause the present burst sequence to terminate and initiates a new read/write full page burst sequence with a new starting address.

So, In addition to the BURST STOP command, PRECHARGE, PRECHARGE ALL or a new read/write commands will terminate a full page burst mode.