AN1176 STMicroelectronics, AN1176 Datasheet - Page 5

• Manufacturer Part Number: AN1176
• Description: 68HC11/PSD813F1 DESIGN GUIDE
• Manufacturer: STMicroelectronics

latches can be accessed directly by the MCU in silicon. No extra design effort on your part is
needed. This MCU access feature is great for loadable shift registers, counters, mailboxes, state
machines, etc. There are 27 I/O pins that generously replace the 68HC11 I/O pins that are
sacrificed to external memory address and data lines. A power management scheme can
selectively shut down parts of the chip and tailor special power saving mechanisms on the fly.
The security feature can block access to all areas of the chip from a device programmer/reader.
And finally, the self-contained JTAG controller allows ISP of all areas of the chip, even on a
completely blank device that is soldered onto a circuit board.
2 Simple Design Example
The first design example will outline the steps to get a flash 68HC11 system up and running
quickly. You will see a connection diagram, a memory map, and the necessary design entry in
the PSDsoft software development environment. A PSD813F1 is used in this example, but the
other members of the FLASH family may be used instead, with minor changes. See the
PSD813F data sheet for a comparison of family members.
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3
PSD813F1
Figure 3 – Top Level Block Diagram of PSD813F1
D E C O D E
P O W E R
M N G T
P A G E
R E G
P L D
C O N T R O L L E R
M C U A D D R /D A T A /C N T L B U S
JT A G
2 4 In p u t L a tch e s
2 K B yte S R A M
1 6 M a cro ce lls
8 se gm e n ts
4 se gm e n ts
1 2 8 K B yte
E E P R O M
3 2 K B yte
F L A S H
C P L D