w78e516b Winbond Electronics Corp America, w78e516b Datasheet - Page 16

• Manufacturer Part Number: w78e516b
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

5.13 In-System Programming Control Register (CHPCON)
CHPCON (BFH)
F04KBOOT Mode (Boot from LDROM)
By default, the W78E516B boots from APROM program after a power on reset. On some occasions,
user can force the W78E516B to boot from the LDROM program via following
situation that you need to enter F04KBOOT mode when the APROM program can not run properly
and device can not jump back to LDROM to execute in-system programming function. Then you can
use this F04KBOOT mode to force the W78E516B jumps to LDROM and executes in-system
programming procedure. When you design your system, you may reserve the pins P2.6, P2.7 to
switches or jumpers. For example in a CD-ROM system, you can connect the P2.6 and P2.7 to PLAY
and EJECT buttons on the panel. When the APROM program fails to execute the normal application
program. User can press both two buttons at the same time and then turn on the power of the
personal computer to force the W78E516B to enter the F04KBOOT mode. After power on of personal
computer, you can release both buttons and finish the in-system programming procedure to update
the APROM code. In application system design, user must take care of the P2, P3, ALE, EA and
mode.
PSEN pin value at reset to prevent from accidentally activating the programming mode or F04KBOOT
BIT
7
6
5
4
3
2
1
0
ENAUXRAM
SWRESET
FPROGEN
(F04KMODE)
FBOOTSL
NAME
0
0
-
-
When this bit is set to 1, and both FBOOTSL and FPROGEN are set to 1. It
will enforce microcontroller reset to initial condition just like power on reset.
This action will re-boot the microcontroller and start to normal operation. To
read this bit in logic-1 can determine that the F04KBOOT mode is running.
Reserve.
Reserve.
1: Enable on-chip AUX-RAM.
0: Disable the on-chip AUX-RAM
Must set to 0.
Must set to 0.
The Program Location Select.
0: The Loader Program locates at the 64 KB APROM. 4KB LDROM is
1: The Loader Program locates at the 4 KB memory bank. 64KB APROM is
FLASH EPROM Programming Enable.
= 1: enable. The microcontroller enter the in-system programming mode after
= 0: disable. The on-chip flash memory is read-only. In-system
destination for re-programming.
destination for re-programming.
programmability is disabled.
entering the idle mode and wake-up from interrupt. During in-system
programming mode, the operation of erase, program and read are
achieve when device enters idle mode.
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FUNCTION
Publication Release Date: April 22, 2008
settings.
W78E516B
The possible
Revision A12