C501 Datasheet, PDF (25/48 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C501
OTP Operation
The C501-1E is programmed by usng a modified Quick-Pulse Programming^{TM 1)} algorithm. It differs
from older methods in the value used for V_PP (programming supply voltage) and in the width and
number of the ALE/PROG pulses. The C501-1E contains two signature bytes that can be read and
used by a programming system to identify the device. The signature bytes identify the manufacturer
of the device.
Table 11 shows the logic levels for reading the signature byte, and for programming the program
memory, the encryption table, and the security bits. The circuit configuration and waveforms for
quick-pulse programming are shown in figures 10 to 12.
Table 11
OTP Programming Modes
Mode
RESET PSEN
Read signature
1
0
Program code data
1
0
Verify code data
1
0
Progam encryption table 1
0
Program security bit 1
1
0
Program security bit 2
1
0
ALE/
PROG
1
0
1
0
0
0
EA/V_PP
1
V_PP
1
V_PP
V_PP
V_PP
P2.7
0
1
0
1
1
1
P2.6
0
0
0
0
1
1
P3.7
0
1
1
1
1
0
P3.6
0
1
1
0
1
0
Notes :
1. “0” = valid low for that pin, “1” = valid high for that pin.
2. V_PP = 12.75 V ± 0.25V
3. V_CC = 5 V ± 10% during programming and verification.
4. ALE/PROG receives 25 programming pulses while V_PP is held at 12.75 V. Each programming pulse is low for
100 µs (± 10 µs) and high for a minimum of 10 µs.
1) _{Quick-Pulse Programming}TM _{is a trademark phrase of Intel Corporation}
Semiconductor Group
25
1997-04-01