AT88SC0404C-PI Atmel, AT88SC0404C-PI Datasheet - Page 35

• Manufacturer Part Number: AT88SC0404C-PI
• Manufacturer: Atmel

Specifications of AT88SC0404C-PI

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: PDIP
• Mounting: Through Hole
• Pin Count: 8
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Not Compliant

34
Write Fuses
The fuses may only be "programmed", that is written from '1' to '0'. The write fuses operation is allowed only after
successfully presenting the secure code (Write 7 password). The fuses must be blown sequentially: FAB must be
blown first, CMA may be blown only if FAB is ‘0’, and PER only if CMA is ‘0’. After this command the host must perform
ACK polling.
Table 28. Fuse Writing
Send Checksum
To write data to user zones that require Authentication for write access (AM [1:0] = “00” or “10” in the access register),
the host should first carry out the write command $B0. At this point the memory is unchanged and the device is waiting
for the host to provide a valid checksum before initiating the write cycle. The host sends the checksum it has computed
using the System WRITE command with Address 1 = $02. Only if the checksum is valid will the device initiate the write
cycle. Furthermore, if the device receives an incorrect checksum, it will clear the authentication privilege. After this
command the host must perform ACK polling.
Set User Zone
Before reading and writing data in the user zones, the host must select a zone with this command. At this time the host
chooses whether anti-tearing should be active for this zone.
Table 29. Anti-Tearing
Data written to the configuration memory may be done with anti-tearing enabled by setting Address 1 to $08 of the
Write Configuration Zone command.
To enable anti-tearing for writes to a user zone a Set User Zone command is executed with Address 1 set to $0B. All
subsequent write user zone commands will be executed with anti-tearing enabled until the next Set User Zone
command. Anti-tearing should be turned off if not required, as it would otherwise cause more write cycles than
necessary.
Figure 17. System WRITE
Atmel AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
S
A
R
T
T
Write Config Zone with Anti-Tearing
Set User Zone with Anti-Tearing
Command
1011 0100
Fuse
CMA
PER
FAB
Command Description
C
A
K
Address 1
Fuse ID
0000 xxxx
$06
$04
$00
A
C
K
Address 2
xxxx xxxx
A
C
K
xxxx xxxx
Command
N
$B4
$B4
C
A
K
d7--- ---d0
Addr 1
Data
$0B
$08
A
C
K
Addr 2
zone
addr
Data x N
d7--- ---d0
N ≤ $08
$00
A
C
K
N
O
S
P
T
5211C–SMIC–01/10
Data (N)
N-bytes