AT89LP2052 Datasheet, PDF (67/89 Pages) ATMEL Corporation – 8-bit Microcontroller with 2/4-Kbyte Flash

AT89LP2052/LP4052 [Preliminary]
22.4.13
Write User Fuses
Function:
• Program User Fuses.
• Unimplemented bits should always be written with 1s.
Usage:
1. Bring CS (P3.2) low.
2. Drive P1 to AAh and pulse XTAL1 high.
3. Drive P1 to E1h and pulse XTAL1 high.
4. Drive P1 to 00h and pulse XTAL1 high.
5. Drive P1 to 00h and pulse XTAL1 high.
6. Drive data on P1 and pulse XTAL1 high.
7. Drive CS high.
8. Wait 4 ms, monitor P3.1, or poll data/status.
Figure 22-17. Write User Fuses Sequence
CS
XTAL1
P1
RDY/BSY
AAh
E1h
00h
00h
1111FFFF
22.4.14 Read User Fuses
Function:
• Read status of User Fuses
Usage:
1. Bring CS (P3.2) low.
2. Drive P1 to 0xAA and pulse XTAL1 high.
3. Drive P1 to 0x61 and pulse XTAL1 high.
4. Drive P1 to 0x00 and pulse XTAL1 high.
5. Drive P1 to 0x00 and bring XTAL1 high.
6. Tri-state P1.
7. Bring XTAL1 low.
8. Read data from P1.
9. Drive CS high.
Figure 22-18. Read User Fuses Sequence
CS
XTAL1
P1
AAh
61h
00h
00h
1111FFFF
Note: The waveforms on this page are not to scale.
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