Super Module Board

• designed by Daniel La Marra (DPNC) (http://dpnc.unige.ch/~lamarra/index.php?page=dpnc279)
• SCHEMATICS
  • SMB v1 schematics
  • SMB v2 schematics
• As seen in the picture below, pin 1 for both 40 and 50-pin connectors (left-hand side of the board) is located top-left.

High Voltage

ADC

Chip

• The ADC used in the SMB is model AD7998BRUZ-0 (IC19 and IC18 in SMB schematics)
• The datasheet is this one: 318057847ad7997_8_0.pdf
• I've checked that after enabling the ADC reading (e->do_adc_read =1;), the clock appears ok
  • period = 12 us (~83 kHz)
  • probe points:
    • HSIO interface-board, connector P2, pin 11 (SCLT_0)
    • SMB board, IC19 / IC18, pin 19 (SCL)

• after that, the data-line of the ADC starts to ouput data serially. Every 3.2 ms, it seems that there is a polling of the state of the ADC coming from the HSIO ?

• the protocol seems to be ok, the device answers with the correct address (0x22):
  • the scope screenshot below shows the SCL line (blue channel) and the SDA line (yellow channel). Every logical-bit corresponds in fact to two clock periods (the clock line must be high when interpreting the data-stream).
  • according to the doc concerning the serial interface (page 23 and successive): the master initiates data transfer by establishing a start condition, defined as a high-to-low transition on the serial data line SDA, while the serial clock line (SCL) remains high. This indicates that an address/data stream follows. All slave peripherals connected to the serial bus responds to the start condition and shift in the next eight bits, consisting of a7-bit address (MSB first) plus an R/W bit that determines the direction of the data transfer, that is weather data is written to (0) or read (1) from the slave device.
  • after the R/W bit, it is visible that the device enters into tri-state, and the control of the line is taken by the ADC to send its data

Sub20 MultiInterface USB adaptor

• Model: SUB-20-V Visual (I2C, SPI, GPIO, LCD, Buttons)
• http://www.xdimax.com/sub20/sub20.html
• SUB20 PCB mechanical drawing v1.1
• SUB20 user manual v2.14

-- SergioGonzalez - 03-Jun-2011