ST90135 datasheet(37/190 Pages) STMICROELECTRONICS

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ST90158 - REGISTER AND MEMORY MAP

3 REGISTER AND MEMORY MAP

3.1 MEMORY CONFIGURATION

The Program memory space of the ST90135/158,

0/16/24/32/48/64/K bytes of directly addressable

on-chip memory, is fully available to the user.

The first 256 memory locations from address 0 to

FFh hold the Reset Vector, the Top-Level (Pseudo

Non-Maskable) interrupt, the Divide by Zero Trap

Routine vector and, optionally, the interrupt vector

table for use with the on-chip peripherals and the

external interrupt sources. Apart from this case no

other part of the Program memory has a predeter-

mined function except segment 21h which is re-

served for use by STMicroelectronics.

3.2 EPROM PROGRAMMING

The 65536 bytes of EPROM memory of the

ST90E158 may be programmed by using the

EPROM Programming Boards (EPB) or gang pro-

grammers available from STMicroelectronics.

EPROM Erasing

The EPROM of the windowed package of the

ST90E158 may be erased by exposure to Ultra-Vi-

olet light.

The erasure characteristic of the ST90E158 is

such that erasure begins when the memory is ex-

posed to light with a wave lengths shorter than ap-

proximately 4000Å. It should be noted that sunlight

and some types of fluorescent lamps have wave-

lengths in the range 3000-4000Å. It is thus recom-

mended that the window of the ST90E158 packag-

es be covered by an opaque label to prevent unin-

tentional erasure problems when testing the appli-

cation in such an environment.

The recommended erasure procedure of the

EPROM is the exposure to short wave ultraviolet

light which have a wave-length 2537Å. The inte-

grated dose (i.e. U.V. intensity x exposure time) for

erasure should be a minimum of 15W-sec/cm2.

The erasure time with this dosage is approximate-

ly 30 minutes using an ultraviolet lamp with

12000mW/cm2 power rating. The ST90E158

should be placed within 2.5cm (1 inch) of the lamp

tubes during erasure.

Table 5. First 6 Bytes of Program Space

Address high of Power on Reset routine

Address low of Power on Reset routine

Address high of Divide by zero trap Subroutine

Address low of Divide by zero trap Subroutine

Address high of Top Level Interrupt routine

Address low of Top Level Interrupt routine

ST90135 数据表(PDF) 37 Page - STMicroelectronics

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