ST52F510 datasheet(37/106 Pages) STMICROELECTRONICS

37 / 106 page

ST52F510/F513/F514

37/106

Figure 4.5 Error Handling Procedure

When the device is locked, if memory reading is

attempted, with the exception of the Lock Byte and

ID Code block, the device returns no data and an

error sequence. If memory writing is attempted in

any memory location, the device doesn’t carry out

the command and returns an error sequence.

To unlock the device the

GlobalErase command

must be executed before any writing or reading

command.

4.5 ID Code

Block 3 on Page 48 (030h) can also be read if the

device is locked. The first byte of the block is the

Lock Byte, the other 31 locations are available to

the

user

for

writing

data,

for

example

identification codes to distinguish the firmware

version loaded in the device.

The ID Code must be written before locking the

device: after the device is locked it can only be

read. The use of the Block writing procedure is the

fastest way: both the ID Code and the Lock bytes

are written together. The lock Bytes are sent first

and then the 31 bytes of ID Code follow.

The blocks 0, 1 and 2 on Page 48 can be also be

used for writing data, but they cannot be accessed

when the device is locked.

Note: the ID Code cannot be modified if the device

is locked: it can only be read.

4.6 Error cases

If a wrong command or data is sent to the device,

it generates an error condition by not sending the

acknowledge after the first successive data or

command. Figure 4.5 shows the error sequence.

The error case can be handled by using the

ReadStatus command. This command can be sent

after the error condition is detected; the device

returns a Status Byte containing the error code.

The

ReadStatus command sequence is showed in

Figure 4.5. The list of the error codes is illustrated

in Table 4.3.

Remark:

after

the

ReadStatus

command

execution or after any error, the Start Sequence

must be carried out before sending a new

command.

The Most Significative Bit of the error codes

indicates (when set to ‘1’) that the memory is

locked. When a command, that is not allowed

when the memory is locked, is sent, the “

Not

Allowed” code is sent. If another code is sent with

the MSB to ‘1’ it indicates that the error condition is

not caused by the memory lock, but by the event

related with the code sent.

Warning: when the data writing into a non existing

location is attempted, no error condition is

generated. The user must take care in specifying

the correct page address.

Wrong command/data case handling:

S=Start, P=Stop, A=Acknowledge, NA=Non-acknowledge

From Slave to Master

From Master to Slave

Wrong Command/Data

Command/Data NA

ReadStatus A P

S 10100001

Status Byte NA

Table 4.3 Error codes

Name

Code

Description

Device Locked

xyyyyyyy

x=lock bit (1=device locked), yyyyyyy=error code

Wrong Direction

x0000001

A transmit direction, not correct in the running sequence, has been set

Stop Missed

x0000010

The Master missed generating a necessary Stop Condition

Data Missing

x0000011

The Master missed to send necessary data to the device

Receive Error

x0000100

The data sent by the Master hasn’t been received correctly by the device

Wrong Command

x0000101

The Master sent a wrong command code

Not Allowed

x0000110

A command not allowed when the device is locked has been sent

Wrong Mode

x0010000

A code different form the Programming mode code (00000000) has been sent

ST52F510 数据表(PDF) 37 Page - STMicroelectronics

ST52F510 数据表(HTML) 37 Page - STMicroelectronics

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

数据表下载