Freescale Semiconductor, Inc.
FLASH 2TS Memory
4.3 Functional Description
The FLASH 2TS memory is appropriately named to describe its
2-transistor source-select bit cell. The FLASH 2TS memory is an array
of 2031 bytes with an additional 14 bytes of user vectors and one byte
for block protection. An erased bit reads as a logic 0 and a programmed
bit reads as a logic 1.
The address ranges for the user memory, control register, and vectors
are:
•
•
$7800–$7FEE, user space
$7FEF, reserved — optional ICG trim value, see 8.8.3 ICG Trim
Register
•
•
•
$FFF0, block protect register
$FE08, FLASH 2TS control register
$FFF2–$FFFF, these locations are reserved for user-defined
interrupt and reset vectors
This list is the row architecture for the user space array:
$7800–$7807 (Row 0)
$7808–$780F (Row 1)
$7810–$7817 (Row 2)
$7818–$781F (Row 3)
$7820–$7827 (Row 4)
--------------------------
$7FE8–$7FEF (Row 253)
Program and erase operations are facilitated through control bits in a
memory mapped register. Details for these operations appear later in
this section. Memory in the FLASH 2TS array is organized into pages
within rows. For the 2-Kbyte array on the MC68HC908RFRK2, the page
size is one byte. There are eight pages (or eight bytes) per row.
Programming operations are performed on a page basis, one byte at a
time. Erase operations are performed on a block basis. The minimum
Advance Information
44
MC68HC908RFRK2
FLASH 2TS Memory
MOTOROLA
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