HCS08 datasheet(58/290 Pages) MOTOROLA

58 / 290 page

Memory

MC9S08GB/GT

MOTOROLA

4.6.2 FLASH Options Register (FOPT and NVOPT)

During reset, the contents of the nonvolatile location NVOPT are copied from FLASH into FOPT. Bits 5

through 2 are not used and always read 0. This register may be read at any time, but writes have no meaning

or effect. To change the value in this register, erase and reprogram the NVOPT location in FLASH

memory as usual and then issue a new MCU reset.

KEYEN — Backdoor Key Mechanism Enable

When this bit is 0, the backdoor key mechanism cannot be used to disengage security. The backdoor

key mechanism is accessible only from user (secured) firmware. BDM commands cannot be used to

write key comparison values that would unlock the backdoor key. For more detailed information about

the backdoor key mechanism, refer to 4.5 Security.

1 = If user firmware writes an 8-byte value that matches the nonvolatile backdoor key

(NVBACKKEY through NVBACKKEY+7 in that order), security is temporarily disengaged

until the next MCU reset.

0 = No backdoor key access allowed.

FNORED — Vector Redirection Disable

When this bit is 1, then vector redirection is disabled.

1 = Vector redirection disabled.

0 = Vector redirection enabled.

Table 4-6 FLASH Clock Divider Settings

fBus

PRDIV8

(Binary)

DIV5:DIV0

(Decimal)

fFCLK

Program/Erase Timing Pulse

µs Min, 6.7 µs Max)

20 MHz

192.3 kHz

5.2

µs

10 MHz

200 kHz

µs

8 MHz

200 kHz

µs

4 MHz

200 kHz

µs

2 MHz

200 kHz

µs

1 MHz

200 kHz

µs

200 kHz

µs

150 kHz

6.7

µs

Bit 7

54321

Bit 0

Read:

KEYEN

FNORED

0000

SEC01

SEC00

Write:

Reset:

This register is loaded from nonvolatile location NVOPT during reset.

= Unimplemented or Reserved

Figure 4-5 FLASH Options Register (FOPT)

HCS08 bảng dữ liệu(PDF) 58 Page - Motorola, Inc

HCS08 bảng dữ liệu(HTML) 58 Page - Motorola, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL