Analog Devices ADSP-21992 EZ-KIT LITE, Системное руководство

Страница: 61 / 87

ADSP-21992 EZ-KIT Lite Evaluation System Manual 3-17
EZ-KIT Lite Hardware Reference
Jumpers
JP18-JP21
are used to configure the UART circuitry on the
ADSP-21992 EZ-KIT Lite board.
JP18-JP20
enable the UART circuitry,
and
JP21
enables the required loopback in the UART circuitry.
CAN Interface Jumpers (JP22-JP23)
A CAN transceiver (
U2
) is provided on the CAN interface.
JP22
enables
(2-3 position) or disables (1-2 position) the sleep mode on the CAN trans-
ceiver. If no shunt is present, this mode can be defined by external
circuitry. Connectors
P12
and
P13
provide connections to the user’s CAN
bus and allow easy daisy-chaining of CAN devices. CAN bus termination
of 120 ohms is provided by closing jumper
JP23
.
External SRAM Enable Jumpers (JP24-JP27)
A 64K by 16-bit SRAM IC (
U8
) is provided on the External Memory
Interface (EMI) of the ADSP-21992 EZ-KIT Lite board. External mem-
ory space consists of four memory banks. Memory bank pins
MS3
through
MS0
select banks 3-0, respectively.
JP24–JP27
map the external SRAM to
MS0
,
MS1
,
MS2
, or
MS3
.
!
If using external SRAM, close only one of these 2-pin jumpers at
any one time.
Encoder Interface Jumpers (JP28-JP30)
The ADSP-21992 EZ-KIT Lite board allows you to apply differential
encoder signals to the board at the encoder interface connector (EIU),
P6
.
A differential line receiver IC (
A8
) is provided to convert the differential
encoder signals to single-ended signals for the EIU inputs of the
ADSP-21992. Three 2-pin jumpers (
JP28–JP30
) are provided to enable
this encoder interface circuitry. It is also possible to apply encoder signals
directly to the Encoder Interface of the ADSP-21992 at these jumpers,
when they are open (that is, when no shunt is installed).