A control register of a front-end chip consists of 207 bits, which are summarized in Table 3. When a control register is loaded with non-broadcast address, a front-end chip specified with the address outputs previous contents of the register on a CTRLREG output pad (single-ended CMOS signal), with bit 0 first in time. If it is loaded with a broadcast address, no signal is seen on the pad. The bit stream is received by a controller chip and forwarded to data output (DOUT). So far, a TEM board cannot capture nor store this bit stream. So a TEM board should keep track of control register contents of all the front-end chip in the tracker.
During loading a register, an HDI becomes very noisy. Especially, a fast-OR trigger bounces around, namely, many fake trigger signals will be seen on a fast-OR line (TOUT1-8). A TEM board should ignore these fake fast-OR's while it is loading control register settings.
Table 3: Control Register Contents of Front-end Chip
A control register of a controller chip consists of 7 bits, 1 bit of which is not used and 6 of which are summarized in Table 4. When a control register is loaded with a specific address or a broadcast address, a controller chip specified with the address outputs previous contents of the register on data output DOUT (differential CMOS signal), with bit 0 first in time. With a broadcast address only contents from the bottom layer will be seen at a TEM board. So far, a TEM board cannot capture nor store this bit stream. So a TEM board should keep track of control register contents of all the controller chip in the tracker.
Table 4: Control Register Contents of Controller Chip