hm2_pktuart_read

NAME
SYNTAX
DESCRIPTION
RETURN VALUE
SEE ALSO

NAME

hm2_pktuart_read − read data from a Hostmot2 UART buffer

SYNTAX

int hm2_pktuart_read(char *name, unsigned char data[], rtapi_u8 *num_frames, rtapi_u16 *max_frame_length, rtapi_u16 frame_sizes[])

DESCRIPTION

hm2_pktuart_read reads data from the PktUART "name". "name" is a unique string given to each PktUART during hostmot2 setup. The names of the available channels are printed to standard output during the driver loading process and take the form: hm2_<board name>.<board index>.pktuart.<index> For example hm2_5i25.0.pktuart.0

This function reads a variable number of PktUART packets from the the specified channel. It should be used inside a realtime HAL component registered with the main hostmot2 driver using the function hm2_pktuart_setup in the setup code.

"(*num_frames)*(*max_frame_length)" should be <= sizeof "data", which one tries to estimate or guess before calling the function. If there are more bytes in the buffer than the size of data array is, then RxArraySizeError is returned.

Note that the PktUART MaxFrameSize is 1024 bytes as hard-coded in hostmot2.vhd .

RETURN VALUE

Returns the number of bytes read on success and negative error codes on failure.

"num_frames" which pointer is passed by value is set to the number of successfully datagrams read.

Negative error codes are:
-1 - low level read/write error
-EINVAL - any PktUART configuration error per instance

-HM2_PKTUART_RxStartbitError - Rx mode register error
-HM2_PKTUART_RxOverrunError - Rx mode register error
-HM2_PKTUART_RxRCFIFOError - Rx mode register error

-HM2_PKTUART_RxPacketOverrrunError - Rx count register
error
-HM2_PKTUART_RxPacketStartbitError - Rx count register
error

-HM2_PKTUART_RxPacketSizeZero - the size of the
received packet is zero
-HM2_PKTUART_RxArraySizeError - data array is too
small for all the data in the buffer

Numeric values of the HM2_PKTUART_ error codes are
defined in
src/hal/drivers/mesa-hostmot2/pktuart_errno.h .

SEE ALSO

man hm2_pktuart_setup, man hm2_pktuart_send
See src/hal/drivers/mesa_pktgyro_test.comp for an
example usage.