Preliminary W78LE516
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bit CHPCON.0 the device will enter in-system programming mode after a wake-up from idle mode.
Because device needs proper time to complete the ISP operations before awaken from idle mode,
software may use timer interrupt to control the duration for device wake-up from idle mode. To
perform ISP operation for revising contents of APROM, software located at APROM setting the
CHPCON register then enter idle mode, after awaken from idle mode the device executes the
corresponding interrupt service routine in LDROM. Because the device will clear the program counter
while switching from APROM to LDROM, the first execution of RETI instruction in interrupt service
routine will jump to 00H at LDROM area. The device offers a software reset for switching back to
APROM while the content of APROM has been updated completely.
Setting CHPCON register bit 0,
1 and 7 to logic-1 will result a software reset to reset the CPU
. The software reset serves as a
external reset. This in-system programming feature makes the job easy and efficient in which the
application needs to update firmware frequently. In some applications, the in-system programming
feature make it possible to easily update the system firmware without opening the chassis.
Note: The ISP Mode operates by supply voltage from 3.3V to 5.5V.
SFRAH, SFRAL:
The objective address of on-chip MTP-ROM in the in-system programming mode.
SFRAH contains the high-order byte of address, SFRAL contains the low-order
byte of address.
SFRFD: The programming data for on-chip MTP-ROM in programming mode.
SFRCN:
The control byte of on-chip MTP-ROM programming mode.
SFRCN (C7)
BIT NAME FUNCTION
7 - Reserve.
6 WFWIN On-chip MTP-ROM bank select for in-system programming.
= 0: 64K bytes MTP-ROM bank is selected as destination for re-
programming.
= 1: 4K bytes MTP-ROM bank is selected as destination for re-programming.
5 OEN MTP-ROM output enable.
4 CEN MTP-ROM chip enable.
3, 2, 1, 0
CTRL[3:0]
The flash control signals
MODE WFWIN CTRL<3:0> OEN CEN SFRAH, SFRAL SFRFD
Erase 64KB APROM 0 0010 1 0 X X
Program 64KB APROM 0 0001 1 0 Address in Data in
Read 64KB APROM 0 0000 0 0 Address in Data out
Erase 4KB LDROM 1 0010 1 0 X X
Program 4KB LDROM 1 0001 1 0 Address in Data in
Read 4KB LDROM 1 0000 0 0 Address in Data out
