Design Documentation

TT8V2motherboard, MBARI 101223

4:36 PM 5/29/01 Dave Wright

General:

The TT8V2 motherboard provides a mounting substrate for the TT8 module, as well as several compatible modules. Battery power conditioning and signal interconnect between the modules and the TT8 is provided.


Circuit description:

A power input network is comprised of PTC1, D1, L1 and C1. D1 is a transient suppressor, capable of clamping input overvoltages and reverse polarity conditions. PTC1 serves to limit input current should these events last more than tens of milliseconds. L1 and C1 filter any transients reflected in the Battery Power/Common circuit before sending it to the TT8 main power input. NS1 is a jumper that connects the battery and logic common nets at the power input location. This prevents large transient loads or flyback voltages on the battery connected loads from upsetting logic circuitry.

Regulated +5V is provided by the TT8 and distributed to all the attached modules as Vreg. 

Connectors J4 and J5 provide connection points for the two RS-232 channels on the TT8.

J1-J3 and J6,J7 are the connections between the TT8 and the attached modules. Each connector provides Battery and Logic power on the first four pins, and the remainder are module specific.


Physical:

The motherboard is 2.20" x 9.00" in size. Mounting holes for #6 machine screws are provided in each corner. The various modules mount to both the top and bottom sides of the motherboard with #2 hardware.


Assembly Notes:

Connectors for the modules are sockets compatible with 0.025" posts. J2 and J7 mount on the bottom side of the board. All others mount on the top.

The component side of the attached modules, whether mounting to the top or bottom side, face towards the motherboard.

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