Raw-mode readout

Summary

Raw data refers to 50MHz ADC samples. The memory available in MCE to store such data is 8192x8 bits. Hence, the 14-bit ADC samples are reported in signed 8b format pre-scaled by 2⁶.

Raw data acquisition is only available in certain build of readout-card firmware. The latest firmware to support raw mode is: xxxx

(Raw data acquisition and 4-pole low-pass filter are both memory-intensive features of the MCE readout-card firmware. As a general rule, a given firmware has only one of these features available, e.g., the firmware that has raw mode enabled will not include the filter and vice versa.)

Setup

There are two MCE parameters that have to be set for raw data acquisition:

captr_raw stores a snapshot of row_len samples of num_rows rows for 2 consecutive frames up to 8192 entries for each channel and stores them in MCE memory buffer for readout in raw mode.

data_mode determines the pixel-data readout mode. data mode has to be set to 3 for raw mode.

A typical sequence of commands for data acquisition is:

 wb cc ret_dat_s 1 1
 wb rc1 data_mode 3
 wb rc1 captr_raw 1
 acq_config filename rc1
 acq_go row_len

Considerations

1) Once the raw-buffer of 8192x8b is full, no more samples are stored till a new captr_raw is issued.

2) The raw-buffer is shipped out of MCE in a regular frame format (header + 41x8 + checksum). So the order of data is as follows: (r0c0s0 refers to "row 0, column 0, sample 0")

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