W925EP01 Datasheet, PDF (70/108 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925EP01/ W925EP01FG
In-System Programming Control Register (CHPCON)
CHPCON (EFH)
BIT
NAME
FUNCTION
7 SWRHWB Set this bit to launch a whole device reset that is same as asserting high to
RESET pin, micro-controller will be back to initial state and clear this bit
automatically. To read this bit, its alternate function to indicate the ISP
hardware reboot mode is invoking when read it in high.
6
-
Reserve.
5
LDAP This bit is Read Only.
High: device is executing the program in LD Flash EPROM.
Low: device is executing the program in AP Flash EPROM.
4
-
Reserve.
3
-
Reserve.
2
-
Reserve.
1 FBOOTSL Loader program residence selection. Set to high to route the device fetching
code from LDROM.
0 FPROGEN In System Programming Mode Enable.
Set this bit to launch the ISP mode. Device will operate ISP procedures, such
as Erase, Program and Read operations, according to correlative SFRs
settings. During ISP mode, device achieves ISP operations by the way of IDLE
state. In the other words, device is not indeed in IDLE mode is set bit PCON.1
while ISP is enabled.
Clear this bit to disable ISP mode, device get back to normal operation
including IDLE state.
F04KBOOT Mode (Hardware Reboot from LDROM)
By default, the W925EP01 boots from APROM program after a power on reset. On some occasions,
user can force the W925EP01 to boot from the LDROM program via following settings. The possible
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 W925EP01 jumps to LDROM and executes in-system
programming procedure. When you design your system, you may reserve the pins P4.7 to switches or
jumpers. For example in a CD-ROM system, you can connect the P4.7 to PLAY or EJECT buttons on
the panel. When the APROM program fails to execute the normal application program, user can press
both two buttons (P4.7 & RESET) at the same time and then turn on the power of the personal
computer to force the W925EP01 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, EA and PSEN
pin value at reset to prevent from accidentally activating the programming mode or F04KBOOT mode.
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