DSM2190F4
TYPICAL CONNECTIONS
Figure 6 shows a typical connection scheme.
Many connection possibilities exist since many
DSM pins are multipurpose. This scheme illus-
trates the use of a combined function BSM signal
(functions as BMS and MSx), and many I/O pins. It
also illustrates how to chain the DSM and DSP de-
vices together on the JTAG bus. The JTAG con-
nector definition depends on development and
production environment requirements. A specially
defined connector can be devised to combine the
signals of the FlashLINK and the Analog Devices
emulator. Alternatively, two separate JTAG con-
nectors can be used, one matching the pinout of
FlashLINK and the other matching the emulator pi-
nout.
Keep in mind that signals BMS, IOMS, MSx,
ADDR16, ADDR17, ADDR18 can be connected to
any DSM pin that is a PLD input. I/O pins on Port
B and Port C are more capable (more PLD func-
tions) than Port D pins. It is recommended to use
Port D pins primarily for decode inputs first, leav-
ing pins on Port B and Port C available for general
logic. Figure 6 illustrates a common way to make
connections.
Following are connection options to consider:
Port C JTAG: Figure 6 shows four JTAG signals
(TMS, TCK, TDI, TDO) connected to the DSM. Al-
ternatively, using six-pin JTAG (two more signals,
TSTAT and TERR) can reduce ISP time by as
much as 30% compared to four-pin JTAG. Other
JTAG options include multiplexing JTAG pins with
general I/O (see “Programming In-Circuit using
JTAG ISP” on page 40 and Application Note
AN1153), or not using JTAG at all. If no JTAG is
used, the DSM device has to be programmed on a
conventional programmer before it is installed on
the circuit board. Using no JTAG makes more
DSM I/O available.
Pins PC2 and PD2. If not all 288K address loca-
tions need to be decoded in the DSM, then
ADDR18 on pin PD2 is not needed. In this case,
the IOMS signal can be connected to pin PD2, free-
ing pin PC2 for general I/O usage.
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