XC2200 Derivatives
System Units (Vol. 1 of 2)
Memory Organization
User’s Manual
3-26
V2.1, 2008-08
MemoryX2K, V1.3
Reset to Read
Arguments: –
Definition:
MOV XXAA
H
, XXF0
H
Timing: One cycle command that does not set any “BUSY” flags. But note that an
immediately following write access to the IMB Core is stalled for a few clock cycles during
which the IMB Core is busy with aborting a previous command.
Description: The internal command state machine is reset to initial state and returns to
read mode. An already started programming or erase operation is not affected and will
be continued (the “
” command — i.e. all commands — will anyhow not be
accepted while the IMB Core is busy).
The “
” command is a single cycle command. It can be used during a
command sequence to reset the command interpreter and return the IMB Core into its
initial state. It clears also all error flags in the Flash Status Register IMB_FSR and an
active page mode is aborted. Because all commands are rejected with a SQER while the
IMB Core is busy “
” can not be used to abort an active command mode.
This command clears: PROER, PAGE, SQER, OPER, ISBER, IDBER, DSBER,
DDBER.
Clear Status
Arguments: –
Definition:
MOV XXAA
H
, XXF5
H
Timing: 1-cycle command that does not set any busy flags.
Description: The flags OPER, SQER, PROER, ISBER, IDBER, DSBER, DDBER in
Flash status register are cleared. Additionally, the process status bits (PROG, ERASE,
POWER, MAR) are cleared.
Change Read Margin
Arguments: MR
Definition:
MOV XXAA
H
, XXB0
H
MOV XX54
H
, XXMR
H
Timing: 2-cycle command that sets “BUSY” for around 30 micro seconds.
Description: This command sequence changes the read margin of one flash module.
The address XX of the second move identifies the targeted flash module. The flash
module needs some time to change its read voltage. During this time BUSY is set and
this flash module cannot be accessed. The other flash modules stay readable.