dsp56k - DSP56001 interface device
#include <asm/dsp56k.h>
ssize_t read(int fd, void *data, size_t length);
ssize_t write(int fd, void *data, size_t length);
int ioctl(int fd, DSP56K_UPLOAD, struct dsp56k_upload *program);
int ioctl(int fd, DSP56K_SET_TX_WSIZE, int wsize);
int ioctl(int fd, DSP56K_SET_RX_WSIZE, int wsize);
int ioctl(int fd, DSP56K_HOST_FLAGS, struct dsp56k_host_flags *flags);
int ioctl(int fd, DSP56K_HOST_CMD, int cmd);
The
dsp56k device is a character device with major number 55 and minor
number 0.
The Motorola DSP56001 is a fully programmable 24-bit digital signal processor
found in Atari Falcon030-compatible computers. The
dsp56k special file
is used to control the DSP56001, and to send and receive data using the
bidirectional handshaked host port.
To send a data stream to the signal processor, use
write(2) to the
device, and
read(2) to receive processed data. The data can be sent or
received in 8, 16, 24, or 32-bit quantities on the host side, but will always
be seen as 24-bit quantities in the DSP56001.
The following
ioctl(2) calls are used to control the
dsp56k
device:
- DSP56K_UPLOAD
- resets the DSP56001 and uploads a program. The third
ioctl(2) argument must be a pointer to a struct
dsp56k_upload with members bin pointing to a DSP56001 binary
program, and len set to the length of the program, counted in
24-bit words.
- DSP56K_SET_TX_WSIZE
- sets the transmit word size. Allowed values are in the
range 1 to 4, and is the number of bytes that will be sent at a time to
the DSP56001. These data quantities will either be padded with bytes
containing zero, or truncated to fit the native 24-bit data format of the
DSP56001.
- DSP56K_SET_RX_WSIZE
- sets the receive word size. Allowed values are in the range
1 to 4, and is the number of bytes that will be received at a time from
the DSP56001. These data quantities will either truncated, or padded with
a null byte ('\0') to fit the native 24-bit data format of the
DSP56001.
- DSP56K_HOST_FLAGS
- read and write the host flags. The host flags are four
general-purpose bits that can be read by both the hosting computer and the
DSP56001. Bits 0 and 1 can be written by the host, and bits 2 and 3 can be
written by the DSP56001.
- To access the host flags, the third ioctl(2)
argument must be a pointer to a struct dsp56k_host_flags. If bit 0
or 1 is set in the dir member, the corresponding bit in out
will be written to the host flags. The state of all host flags will be
returned in the lower four bits of the status member.
- DSP56K_HOST_CMD
- sends a host command. Allowed values are in the range 0 to
31, and is a user-defined command handled by the program running in the
DSP56001.
/dev/dsp56k
linux/include/asm-m68k/dsp56k.h,
linux/drivers/char/dsp56k.c,
http://dsp56k.nocrew.org/
DSP56000/DSP56001 Digital Signal Processor User's Manual