AT89LP428-20MU ATMEL [ATMEL Corporation], AT89LP428-20MU Datasheet - Page 124

• Manufacturer Part Number: AT89LP428-20MU
• Description: 8-bit Microcontroller with 4K/8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

23.9.3
23.9.4
124
AT89LP428/828
ISP Start Sequence
ISP Exit Sequence
Execute this sequence to exit CPU execution mode and enter ISP mode when the device has
passed Power-on Reset and is already operational.
Figure 23-7. In-System Programming (ISP) Start Sequence
Execute this sequence to exit ISP mode and resume CPU execution mode.
Figure 23-8. In-System Programming (ISP) Exit Sequence
Note:
1. Drive RST low.
2. Drive SS high.
3. Wait t
4. Start programming session.
1. Drive SCK low.
1. Wait at least t
2. Tristate MOSI.
3. Wait at least t
4. Tristate SCK.
5. Wait t
XTAL1
The waveforms on this page are not to scale.
MISO
MOSI
RST
SCK
V
SS
RLZ
RHZ
CC
XTAL1
MISO
MOSI
SCK
RST
V
SS
+ t
CC
and tristate SS.
STL
SSD
SSZ
.
and bring RST high.
and drive SS high.
t
SSD
t
SSZ
t
t
RLZ
RHZ
HIGH Z
HIGH Z
t
STL
HIGH Z
HIGH Z
t
ZSS
t
SSE
3654A–MICRO–8/09