Texas Instruments TMS320F20x/F24x DSP manual ±3. Segment Control Register Field Descriptions

PRELIMINARY

Flash Module Control Registers

Table 2±3. Segment Control Register Field Descriptions

Bits	Name	Description
15±8	SEG7±SEG0	Segment enable bits. Each of these bits protects the specified segment against pro-
		gramming or enables programming for the specified segment in the array. Any number
		of segments (from 0 to 7 in any combination) can be enabled at any one time. See
		Table 2±4 for segment address ranges. EXE must be cleared to modify the SEGx bits.
		SEGx = 1 enables programming of the corresponding segment.
		SEGx = 0 protects the segment from programming.
7	Reserved	This bit is not affected by writes, and reads of this bit are undefined.
6±5	KEY1, KEY0	Execute key bits. A binary value of 10 must be written to these bits in the same DSP
		core access in which the EXE bit is set for the selected operation (erase, program, or
		flash-write) to start. KEY1 and KEY0 must be cleared in the same write access that
		clears EXE. These bits are used as additional protection against inadvertent program-
		ming or erasure of the array. These bits are read as 0s.
4±3	VER0, VER1	Verify bits. These bits select special read modes used to verify proper erasure or pro-
		gramming.
		Possible values:
		00: Normal read mode
		01: Verify 1s (VER1) read mode to verify margin of 1s for proper erasure
		10: Verify 0s (VER0) read mode to verify margin of 0s for proper programming
		11: Inverse-read mode; tests for bits erased into depletion
2±1	WRITE/ERASE	Write/erase enable field. These bits select the program, erase, or flash-write operation.
		However, modification of the array data does not actually start until the EXE bit is set.
		Reset clears these bits to zero.
		Possible values:
		00: Read operation is enabled. These bit values are required to read the array.
		01: Erase operation is enabled
		10: Write operation is enabled
		11: Flash-write operation is enabled
0	EXE	Execute bit. In conjunction with WRITE/ERASE, KEY1, and KEY0, this bit controls the
		program, erase, and flash-write operations. Setting EXE starts and stops program-
		ming and erasing of the flash array. The KEY1 and KEY0 bits must be written in the
		same write access that sets EXE, and EXE must be cleared in the same write access
		that clears KEY1 and KEY0. EXE must be cleared to modify the SEGx bits.
Note:	The segment enable bits are not intended for protection during the erase or flash-write operations. During these opera-
	tions, all segments must be enabled.

PRELIMINARY Flash Operations and Control Registers 2-9