Variables Used in the Routines

On-Chip FLASH Programming Routines, Rev. 4

Freescale Semiconductor

3

ERARNGE

This routine is used to erase either a page (64 bytes) or the whole array of FLASH. It can be used when

DELNUS

This routine can generate a specified delay based on the values of register X and accumulator (A) as

parameters. DELNUS is used in ERARNGE routine.

Variables Used in the Routines

The RDVRNGE, PRGRNGE, and ERARNGE routines require certain registers and/or RAM locations to

and their locations.

RAM

specific MCUs. For example, the RAM start address for the MC68HC908LB8 (and each MCU currently

in the table) is $80.

CTRLBYT

The control byte (CTRLBYT) is located at RAM address RAM+$8 and is used for the ERARNGE routine.

In the case of the MC68HC908LB8, the CTRLBYT is located at $88. Bit 6 in this location is used to specify

either MASS (1) or PAGE (0) erase. The other bits must be 0. If one or more of these bits (except bit 6)

is initialized with 1, the erase operation is not executed.

Table 1. Variables and Their Locations

Location

Variable Name

Size (Bytes)

Description

RAM – RAM+7

Reserved

8

Reserved for future use

RAM+$8

CTRLBYT

1

Control byte setting erase size

RAM+$9

CPUSPD

1

CPU speed — the nearest integer of

for example, if

RAM+$A,

RAM+$B

LADDR

2

Last address of a 16-bit range

RAM+$C

DATA

Varies

First location of DATA array;

DATA array size must match a programming or verifying range

Registers H:X

—

2

Beginning address of a 16-bit range