Resetting Chips

There are a three ways to reset a front-end chip or a controller chip; by command, by a reset pulse, or by turning on power. The result of resetting varies depending on how it is reset as described below.

A reset pulse is a single-ended CMOS digital signal. There is a reset pad both on a front-end chip and on a controller chip, and they are connected on an HDI together. Also, they are connected to each other on a Kapton readout cable. Therefore, if you send a reset signal to one of the cables, you are resetting all the front-end chips and the controller chips connected on the cable.

Reset pulse

A reset pulse resets a command decoder of the front-end chip. It does not change contents of control register. A reset pulse to a controller chip resets resets control register and readout flags of the controller chip. So, if you send a reset pulse to the tracker, you have to reconfigure controller chips but not front-end chips.

Reset-chip command to front-end chip

A reset-chip command to a front-end chip resets a command decoder, a control register, and FIFO. Note, if you send a reset-chip command to front-end chips, you should reload control register of the front-end chips.

Reset-chip command to controller chip

A reset-chip command to a controller chip resets readout flags, but not its control register. To maintain consistency between front-end chips and a controller chip, you should reset FIFO's of front-end chips also, when you send a reset-chip command to a controller chip.

Reset-FIFO command to front-end chip

A reset-FIFO command resets a FIFO of specified front-end chip(s), namely, erases all the contents of the FIFO.

Power-on Reset

Both a front-end chip and a controller chip has a power-on reset feature. It sets a default setting to a control register, clears a FIFO, resets a command decoder, and so on.