SAM Printf Queue Sampler

Used to read out data from a queue on a SAM device.

The printf queue is a circular buffer stored in the SAM's SRAM space along with some administrative functions. It consists of:
  1. 1.1 word token+size ("SAM"+size_bytes).
  2. 2.1 word write pointer.
  3. 3.1 word read pointer.
  4. 4.(2^size)-12 bytes circular buffer.

The printf queue sampler reads available bytes from the read pointer and sends data to the host computer.

Table 1. SAM Printf Queue Sampler
Field Size Description
DATA_SAMPLER 1 byte 0x8A
SAMPLE_PRINTF_QUEUE 1 byte 0x04
ENABLE 1 byte

0x00: disable

0x01: enable
ADDRESS 4 byte Start address of queue structure to poll, MSB first
FLAGS 4 byte
Bits 1:0: destination:
  • b00: send to DGI as data
  • b01: send to HID (reserved)
  • b10: send to DGI as print
  • b11: reserved

Response:

Table 2. SAM Printf Queue Sampler Response
Field Size Description
DATA_SAMPLER 1 byte 0x8A
SAMPLE_PRINTF_QUEUE 1 byte 0x04
Status 1 byte

Status code

0x00: OK

0xFF: Error
Note: This feature is in a beta stage and should be used with caution.
Parent topic: Data Polling Service