Texas Instruments MSP430x11x1 flash memory, timing generator, control register FCTL2, Erase

MSP430x11x1

MIXED SIGNAL MICROCONTROLLER

SLAS241C ± SEPTEMBER 1999 ± REVISED JUNE 2000

flash memory control register FCTL1 (continued)

Read access is possible at any time without restrictions.

The control bits of control register FCTL1 are:

15

FCTL1

0128h

8	7							0
	SEG	WRT	res.	res.	res.	MEras	Erase	res.
	WRT
	rw±0 rw±0		r0	r0	r0	rw±0	rw-0	r0

FCTL1 read:		096h
FCTL1 write:
		0A5h
Erase	0128h, bit1, Erase a segment

0:No segment erase will be started.

1:Erase of one segment is enabled. The segment to be erased is defined by a dummy write into any address within the segment. The erase bit is automatically reset when the erase operation is completed.

MEras 0128h, bit2, Mass Erase, main memory segments are erased together.

0:No segment erase will be started.

1:Erase of main memory segments is enabled. Erase starts when a dummy write to any address in main memory is executed. The MEras bit is automatically reset when the erase operation is completed.

WRT 0128h, bit6, Bit WRT must be set for a successful write execution.

If bit WRT is reset and write access to the flash memory is attempted, an access violation occurs and ACVIFG is set.

SEGWRT 0128h, bit7, Bit SEGWRT may be used to reduce total programming time.

Refer to MSP430x1xx User's Guide, literature number SLAU049 for details.

0:No segment-write acceleration is selected.

1:Segment-write is used. This bit needs to be reset and set between segment borders.

Table 3. Allowed Combinations of Control Bits Allowed for Flash Memory Access

FUNCTION PERFORMED	SEGWRT	WRT	MEras	Erase	BUSY	WAIT	Lock
Write word or byte	0	1	0	0	0	0	0
Write word or byte in same segment, segment write mode	1	1	0	0	0 → 1	0 → 1	0
Erase one segment by writing to any address in the target segment	0	0	0	1	0	0	0
Erase all segments (0 to 7) but not the information memory	0	0	1	0	0	0	0
(segments A and B)
Erase all segments (0 to 7 and A and B) by writing to any address in	0	0	1	1	0	0	0
the flash memory module

NOTE: The table shows all valid combinations. Any other combination will result in an access violation.

flash memory, timing generator, control register FCTL2

The timing generator (Figure 1) generates all the timing signals necessary for write, erase, and mass erase from the selected clock source. One of three different clock sources may be selected by control bits SSEL0 and SSEL1 in control register FCTL2. The selected clock source should be divided to meet the frequency requirements specified in the recommended operating conditions.

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