ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 363 -
Revision 2.4
Power
On
CBS = 1 ?
Fetch code from
APROM
Fetch code from
LDROM
Execute ISP?
Enable ISPEN
Set ISPTRIG = 1
End of ISP
operation
?
(Read ISPDAT)
Check ISPFF = 1?
YES
YES
NO
B
Update LD-ROM or
write DataFlash
End of Flash Operation
A
A
Clear BS to 0 and set
SWRST = 1 to reboot in
APROM
C
C
B
A
B
Clear ISPEN and return
to main program
NO
Write
ISPADR/ ISPCMD/
ISPDAT
Figure 6-5 Boot Sequence and ISP Procedure
The ISP command set is shown in Table 6-4. Three registers determine the action of a command:
FMC_ISPCMD is the command register and accepts commands for reading ID registers and
read/write/erase of flash memory. The FMC_ISPADDR is the address register where the flash memory
address for access is written. FMC_ISPDAT is the data register that input data is written to and return
data read from. An ISP command is executed by setting FMC_ISPCMD, FMC_ISPDAT and
FMC_ISPADDR then writing to the trigger register ISPTRIG.
Table 6-4 ISP Command Set
ISP Mode
FMC_ISPCMD
FMC_ISPADDR
FMC_ISPDAT
CMD[5:0]
A21
A20
A[19:0]
D[31:0]
Standby
0x3x
x
x
x
x
