stf1001 Shanghai Fudan Microelectronics Co., Ltd., stf1001 Datasheet - Page 7

• Manufacturer Part Number: stf1001
• Description: Stf1001 Telephone Ic Card Chip
• Manufacturer: Shanghai Fudan Microelectronics Co., Ltd.

4.
STF1001 Telephone IC Card Chip
Count Unit
The Counter Area consists of a preloaded five stage counter as 5-digit octal counter. The
highest counter stage 5 representing a value of 8
representing a value of 8
Therefore a maximum number of units is
8*8
In practice the range is reduced to 33352 units due to the personalization bit (address 64).
Counting is done by writing bits from “1” to “0”. If there are not enough bits in stage the erasing
with carry has to be applied.
The erasing with carry consists of two consecutive write operations. The first pulse writes a
carry bit in higher stage m to “0”, the second pulse at same address erase all 8 bits of the lower
stage m-1 to “1”.
The counter stage 1 to 4 may completely be erased to “1”. The highest counter stage 5 is not
erasable, thus counter can be limited to certain number of units.
4
+8*8
3
+8*8
2
+8*8
1
+8*8
0
0
unit.
=37448
Ver 1.1
4
units;
The lowest counter stage 1
Specification
7