Rainbow Electronics AT89LP216 - Manual (Page 73)

73
3621A–MICRO–6/06
AT89LP216 [Preliminary]
23.8.3 ISP Start 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.
1. Drive RST low.
2. Drive SS high.
3. Wait t
RLZ
+ t
STL
.
4. Start programming session.
Figure 23-7. In-System Programming (ISP) Start Sequence
23.8.4 ISP Exit Sequence
Execute this sequence to exit ISP mode and resume CPU execution mode.
1. Drive SCK low.
1. Wait at least t
SSD
and drive SS high.
2. Tristate MOSI.
3. Wait at least t
SSZ
and bring RST high.
4. Tristate SCK.
5. Wait t
RHZ
and tristate SS.
Figure 23-8. In-System Programming (ISP) Exit Sequence
Note: The waveforms on this page are not to scale.
t
STL
V
CC
RST
SS
SCK
HIGH Z MOSI
HIGH Z MISO
XTAL1
t
RLZ
t
ZSS
t
SSE
V
CC
RST
SS
SCK
HIGH Z MOSI
HIGH Z MISO
XTAL1
t
SSZ
t
SSD
t
RHZ