Danville Signal Processing dspstak 21262sx, User Manual

Page: 30 / 35

Memory Map
Name Addr Dir Bits Used Description
USB_DATA 0x8000 R/W D7-D0 USB Data Bus
USB_STATUS 0x9000 R D15-D12 USB Status
PLD_DAI_SPI_SELECT 0xA000 W D15-D12 Selects between IO & SPISSs
PLD_OUT0 0xB000 W D15-D12 LED3 – LED0
PLD_OUT1 0xC000 W D15-D12 LED4 & #RESETs
PLD_SPI_SELECT 0xD000 W D15-D12 SPI Mask
PLD_WD 0xE000 W None Watchdog Strobe
User Space (JH2) <0x8000 This space is available to external
devices
User Space (JH2) 0xF000 This space is available to external
devices
USB Port
The USB port on the dspstak 21262sx uses an FTDI FT245BM USB transceiver. This device is a USB
2.0 compliant, full speed part (12Mb/s). This part is very easy to use since in most cases it just looks
like a COM Port to the USB Master. FTDI has royalty free device drivers on their web site that
support a variety of operating systems. We suggest that you visit their web site ( www.ftdichip.com )
for additional information.
We supply Windows® drivers on our distribution CD. The driver files includes dspstak *.inf files
that are used for installation in Microsoft Windows® operating systems. If you are using another OS,
you may want to compare the ftdibus.inf and ftdiport.inf files to the dspstakbus.inf and
dspstakport.inf files to configure your driver. Instructions on installing the Windows® drivers are on
the CD.
The FT245BM has receive and transmit FIFOs that are read from or written to the DSP. There are
three USB status bits: RXF, TXE and PWREN. PWREN is low when the USB port is enumerated
(recognized by the USB Master). If RXF is low, you can receive one byte; if TXE is low, you can
transmit one byte. There is no guarantee that the USB port can accept or deliver more than one
byte based on the flags, therefore you must check the status before sending or receiving the next
byte.
Reading and writing the Parallel Port is more complicated than a simple I/O or Memory R/W
instruction. You will want to review the Analog Devices documentation and the sample code
provided on our Distribution CD to see how it’s done in detail.
dspstak™ 21262sx User Manual
Page 30