CP3BT23_14 Datasheet, PDF (41/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CP3BT23
www.ti.com
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
8.4.2 Protection Word
The Protection Word resides in Information Block 1 at address 0FEh. At reset, the Protection Word is
copied into the FMAR1 register.
15
13
WRPROT
12
10
RDPROT
9
7
ISPE
6
4
EMPTY
3
1
0
BOOTAREA
BOOTARE The BOOTAREA field specifies the size of the Boot Area. The Boot Area starts at address 0
A
and ends at the address specified by this field. The inverted bits of the BOOTAREA field
count the number of 2048-byte blocks to be reserved as the Boot Area. The maximum Boot
Area size is 30K bytes (address range 0 to 77FFh). The end of the Boot Area defines the
start of the Code Area. If the device starts in ISP mode and there is no Boot Area defined
(encoding 1111b), the device is kept in reset.
Table 8-5 lists all possible boot area encodings.
BOOT AREA
1111
1110
1101
1100
1011
1010
1001
1000
0111
0110
0101
0100
0011
0010
0001
0000
Table 8-5. Boot Area Encodings
Size of the Boot Area
No Boot Area defined
2K bytes
4K bytes
6K bytes
8K bytes
10K bytes
12K bytes
14K bytes
16K bytes
18K bytes
20K bytes
22K bytes
24K bytes
26K bytes
28K bytes
30K bytes
Code Area Start Address
00 0000h
00 0800h
00 1000h
00 1800h
00 2000h
00 2800h
00 3000h
00 3800h
00 4000h
00 4800h
00 5000h
00 5800h
00 6000h
00 6800h
00 7000h
00 7800h
EMPTY
ISPE
The EMPTY field indicates whether the flash program memory has been programmed or
should be treated as blank. If a majority of the three EMPTY bits are clear, the flash
program memory is treated as programmed. If a majority of the EMPTY bits are set, the
flash program memory is treated as empty. If the ENV[1:0] inputs (see Section 6.1) are
sampled high at reset and the EMPTY bits indicate the flash program memory is empty, the
device will begin execution in ISP mode. The device enters ISP mode without regard to the
EMPTY status if ENV0 is driven low and ENV1 is driven high.
The ISPE field indicates whether the Boot Area is used to hold In-System-Programming
routines or user application routines. If a majority of the three ISPE bits are set, the Boot
Area is intended to store ISP routines. If majority of the ISPE bits are clear, the Boot Area
holds user application routines. Table 8-6 summarizes all possible EMPTY, ISPE, and Boot
Area settings and the corresponding start-up operation for each combination. In DEV mode,
the EMPTY bit settings are ignored and the CPU always starts executing from address 0.
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