Rainbow Electronics ATmega128RFA1 - Manual (Page 452)

452
8266A-MCU Wireless-12/09
ATmega128RFA1
programming is completed, the RWWSB must be cleared by software before reading
code located in the RWW section. See
"SPMCSR – Store Program Memory Control
Register" on page 462 for details on how to clear RWWSB.
30.3.2 NRWW – No Read-While-Write Section
The code located in the NRWW section can be read when the Boot Loader software is
updating a page in the RWW section. When the Boot Loader code updates the NRWW
section, the CPU is halted during the entire Page Erase or Page Write operation.
Table 30-1. Read-While-Write Features
Which Section does the Z-pointer
Address during the Programming?
Which Section can be Read
during Programming? CPU Halted?
Read-While-Write
Supported?
RWW Section NRWW Section No Yes
NRWW Section None Yes No
Figure 30-2. Memory Sections
0x0000
Flashend
Program Memory
BOOTSZ = '11'
Application Flash Section
Boot Loader Flash Section
Flashend
Program Memory
BOOTSZ = '10'
0x0000
Program Memory
BOOTSZ = '01'
Program Memory
BOOTSZ = '00'
Application Flash Section
Boot Loader Flash Section
0x0000
Flashend
Application Flash Section
Flashend
End RWW
Start NRWW
Application Flash Section
Boot Loader Flash Section
Boot Loader Flash Section
End RWW
Start NRWW
End RWW
Start NRWW
0x0000
End RWW, End Application
Start NRWW, Start Boot Loader
Application Flash Section Application Flash Section
Application Flash Section
Read-While-Wr
ite Section
No Read-While-Wr
ite Section
Read-While-Wr
ite Section
No Read-While-Wr
ite Section
Read-While-Wr
ite Section
No Read-While-Wr
ite Section
Read-While-Wr
ite Section
No Read-While-Wr
ite Section
End Application
Start Boot Loader
End Application
Start Boot Loader
End Application
Start Boot Loader
Note: 1. The parameters in the figure above are given in Table 30-7 on page 461 .