Datasheet

Table Of Contents
MC68HC908GP20Rev 2.1 Advance Information
Freescale Semiconductor 169
Advance Information MC68HC908GP20
Section 11. FLASH Memory
11.1 Contents
11.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
11.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
11.4 FLASH Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171
11.5 Charge Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
11.5.1 FLASH Charge Pump Frequency Control. . . . . . . . . . . . .173
11.5.2 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
11.6 FLASH Erase Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
11.7 FLASH Program/Margin Read Operation. . . . . . . . . . . . . . . .177
11.8 FLASH Block Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180
11.9 FLASH Block Protect Register . . . . . . . . . . . . . . . . . . . . . . . .181
11.10 Wait Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
11.11 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
11.2 Introduction
This section describes the operation of the embedded FLASH memory.
This memory can be read, programmed, and erased from a single
external supply. The program, erase, and read operations are enabled
through the use of an internal charge pump.
11.3 Functional Description
The FLASH memory is an array of 19,968 bytes with an additional 36
bytes of user vectors and one byte of block protection. An erased bit
reads as logic 0 and a programmed bit reads as a logic 1. Program and
erase operations are facilitated through control bits in a memory mapped
register. Details for these operations appear later in this section. Memory