/* choice byte-programming command */

/* set ISPEN=1 to enable flash change.

set WAIT=010, 60 MC; assumed 10M X’s*/

IFADRH ← (Address high byte)

/* specify the address to be programmed */

IFADRL ← (Address low byte)

IFD ← (byte date to be written into flash)

/* prepare data source */

SCMD ← 46h

/* trig ISP activity */

SCMD ← B9h

(CPU progressing will be hold here)

(CPU continues)

Program a byte into flash

/* choice byte-read command */

/* set ISPEN=1 to enable flash change.

set WAIT=010, 11 MC; assumed 10M X’s*/

IFADRH ← (Address high byte)

/* specify the address to be read */

IFADRL ← (Address low byte)

SCMD ← 46h

/* trig ISP activity */

SCMD ← B9h

(CPU progressing will be hold here)

(CPU continues and currently IFD contain the desired data byte )

Read a byte from flash

Booting Program Entrance

The MPC89x53A boots according to the following rule.

System will boot from normal AP program

else

System will boot from ISP program

If

( HWBS == 0 )

Above rule is adaptive only for power-up procedure, while not software reset.

Switching from ISP program to AP program

The device permits the user normally start running the AP program as soon as the ISP

program has finished updating the flash content. Just program an instruction at the tail of ISP

program as

ISPCR ←

001xxxxx

b

30

MPC89x53A Data Sheet

MEGAWIN