ST6255C View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST6255C' PDF : 84 Pages View PDF
ST6255C ST6265C ST6265B
8.3 ROM DEVICES
The ST6255C and ST6265B are mask pro-
grammed ROM versions.
They offer the same functionality as OTP devices,
selecting as ROM options the options defined in
the programmable option byte of the OTP version,
except the LVD & OSG options that are not availa-
ble on the ST6265B ROM device.
Figure 54. Programming Waveform
Figure 55. Programming Circuit
5V 47mF
100nF
TEST
15
14V typ
10
5
TEST
0.5s min
150 µs typ
VSS
VDD
TEST
100nF
PROTECT
14V
ZPD15
15V
VR02003
100mA
max
Note: ZPD15 is used for overvoltage protection
4mA typ
t
VR02001
8.3.1 ROM READOUT PROTECTION
If the ROM READOUT PROTECTION option is
selected, a protection fuse can be blown to pre-
vent any access to the program memory content.
In case the user wants to blow this fuse, high volt-
age must be applied on the TEST pin.
8.3.2 Transfer of Customer Code
Customer code is made up of the ROM contents
and the list of the selected mask options. The
ROM contents are to be sent on diskette, or by
electronic means, with the hexadecimal file gener-
ated by the development tool. All unused bytes
must be set to FFh.
The selected mask options are communicated to
STMicroelectronics using the correctly filled OP-
TION LIST appended. See page 82.
8.3.3 Listing Generation and Verification
When STMicroelectronics receives the user’s
ROM contents, a computer listing is generated
from it. This listing refers exactly to the mask which
will be used to produce the specified MCU. The
listing is then returned to the customer who must
thoroughly check, complete, sign and return it to
STMicroelectronics. The signed listing forms a
part of the contractual agreement for the creation
of the specific customer mask.
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