w79e532 Winbond Electronics Corp America, w79e532 Datasheet - Page 58

• Manufacturer Part Number: w79e532
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

14. H/W REBOOT MODE (BOOT FROM 4K BYTES OF LDFLASH)
The W79E(L)532 boots from APFlash program (64K bytes) by default at the external reset. On some
occasions, user can force W79E(L)532 to boot from the LDFlash program (4K bytes) at the external
reset. The settings for this special mode is as follow. It is necessary to add 10K resistor on these P2.6,
P2.7 and P4.3 pins.
Reboot Mode
Notes:
1. The possible situation that you need to enter REBOOT mode is when the APFlash program can not run normally and
2: In application system design, user must take care the P4.3, P2, P3, ALE, /EA and /PSEN pin value at reset to avoid
W79E(L)532 can not jump to LDFlash to execute on chip programming function. Then you can use this REBOOT mode to
force the CPU jump to LDFlash and run on chip programming procedure. When you design your system, you can connect
the pins P26, P27 to switches or jumpers. For example in a CD ROM system, you can connect the P26 and P27 to PLAY
and EJECT buttons on the panel. When the APFlash program is fail to execute the normal application program. User can
press both two buttons at the same time and then switch on the power of the personal computer to force the W79E(L)532 to
enter the REBOOT mode. After power on of personal computer, you can release both PLAY and EJECT button. And re-run
the on chip programming procedure to let the APFlash have the normal program code. Then you can back to normal
condition of CD ROM.
W79E(L)532 entering the programming mode or REBOOT mode in normal operation.
OPTION BITS
Bit4 L
Bit5 L
RST
P2.7
P2.6
RST
H
H
The Reset Timing For Entering
P4.3
20 US
X
L
REBOOT Mode
- 58 -
P2.7
X
L
10 mS
P2.6
X
L
W79E532/W79L532
Hi-Z
Hi-Z
REBOOT
REBOOT
MODE