Texas Instruments ADS1254, Руководство пользователя

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Connectors
3-8
3.3.6 J8: External Digital Control
Header J8 provides access to certain signals connected between the DSK and
the ADS1254. It can also be used as an additional place to connect external
equipment for communicating with the ADS1254.
Table 3−10.J8: 3.3-V JTAG Port
Pin
Number Pin
Symbol Signal
Name Direction
(at board) Function
1 NC − − Not connected
3 HOST_CLKXA SERIAL_CLK Input SPI clock for ADS1254
5 HOST_CLKRA HOST_CLKRA Output SPI clock from board; not used
7 HOST_DXA HOST_DXA Output SPI data from board; not used
9 HOST_DRA HOST_DRA Input SPI data for ADS1254 from DSK
11 HOST_FSXA HOST_FSXA Output Frame sync from board; not used
13 HOST_FSRA HOST_FSRA Input Frame sync from DSK; not used
15 HOST_CLKOUT HOST_CLKOUT − Not used
17 HOST_CLKSA HOST_CLKSA − Not used
19 NC − − Not connected
Even-numbered
pins DGND DGND Power Signal ground
3.3.7 J9, J10: DSK Motherboard Connectors
These two connectors are used as both electrical connection and mechanical
support for plugging the ADS1254EVM into a DSP DSK. Communication
between a DSP on a DSK and the ADS1254 on the EVM is accomplished
through these connectors.
J9, the memory interface connector, carries the DSP external bus. J10, the
peripheral and control connector, carries various GPIO and peripheral signals
from the DSP.
The ADS1254, being a purely SPI part, does not make use of the DSP external
parallel bus; therefore, only one signal connection from J9, a timer output, is
used.
J10 carries the DSK serial channels. Texas Instruments DSPs currently
available on DSKs incorporate a multichannel buffered serial port, or McBSP,
which among other things supports full-duplex SPI and a frame-sync signal.
The ADS1254 has neither of these, so only the McBSPs SPI clock and data
outputs are connected. The other McBSP signals are brought to J8 for
convenience.