DS89C430 datasheet(25/48 Pages) DALLAS

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DS89C430/DS89C440/DS89C450 Ultra-High-Speed Flash Microcontrollers

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ROM Loader

The full on-chip flash program memory space, security flash block, and external SRAM can be programmed in-

system from an external source through serial port 0 under the control of a built-in ROM loader. The ROM loader

also has an auto-baud feature that determines which baud-rate frequencies are being used for communication and

sets the baud-rate generator for that speed.

When the DS89C430 is powered up and has entered its user operating mode, the ROM loader mode can be

invoked at any time by forcing RST = 1,

EA = 0, and PSEN = 0. It remains in effect until power-down or when the

condition (RST = 1 and

PSEN = EA = 0) is removed. Entering the ROM loader mode forces the processor to start

fetching from the 2kB internal ROM for program memory initialization and other loader functions.

The read/write accessibility is determined by the state of the lock bits, which can be verified directly by the ROM

loader.

The flash memory can be programmed (by the built-in ROM loader) using commands that are received over the

serial interface from a host PC. Full details of the ROM loader commands are given in the Ultra-High-Speed Flash

Microcontroller User’s Guide. Host software to communicate with the ROM loader is available in Windows® format

as well as other platforms. Contact our technical support department at micro.support@dalsemi.com for more

information.

Parallel Programming Mode

The microcontroller also supports a programming mode such as that used by commercial device programmers.

This mode is of little utility in normal applications and is only used by commercial device programmers. For

information on this mode, contact our technical support department at micro.support@dalsemi.com.

Data Pointer Increment/Decrement and Options

The DS89C430 incorporates a hardware feature to assist applications that require data pointer increment/

decrement. Data pointer increment/decrement bits ID0 and ID1 (DPS.6 and DPS.7) define how the INC DPTR

instruction functions in relation to the active DPTR (selected by the SEL bit). Setting ID0 = 1 and SEL = 0 enables

the decrement operation for DPTR, and execution of the INC DPTR instruction decrements the DPTR contents

by 1. Similarly, setting ID1 = 1 and SEL = 1 enables the decrement operation for DPTR1, and execution of the INC

DPTR instruction decrements the DPTR1 contents by 1. With this feature, the user can configure the data pointers

to operate in four ways for the INC DPTR instruction:

ID1

ID0

SEL = 0

SEL = 1

INC DPTR

INC DPTR1

DEC DPTR

INC DPTR1

INC DPTR

DEC DPTR1

DEC DPTR

DEC DPTR1

SEL (DPS.0) bit always selects the active data pointer. The DS89C430 offers a programmable option that allows

any instructions related to data pointer to toggle the SEL bit automatically. This option is enabled by setting the

toggle-select-enable bit (TSL–DPS.5) to a logic 1. Once enabled, the SEL bit is automatically toggled after the

execution of one of the following five DPTR-related instructions:

INC DPTR

MOV DPTR #data16

MOVC A, @A+DPTR

MOVX A, @DPTR

MOVX @DPTR, A

The DS89C430 also offers a programmable option that automatically increases (or decreases) the contents of the

selected data pointer by 1 after the execution of a DPTR-related instruction. The actual function (increment or

decrement) is dependent on the setting of the ID1 and ID0 bits. This option is enabled by setting the automatic

increment/decrement enable (AID–DPS.4) to a logic 1 and is affected by the following three instructions:

MOVC A, @A+DPTR

MOVX A, @DPTR

MOVX @DPTR, A

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