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ASIM team
LIP6 Laboratory
Paris, France |
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Figure 7.3:
Macrocells connected together
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The boot protocol of the RCube HSL links is implemented in a finite state machine (one by
serial link). The calibration procedure between two serial macrocells, belonging to two
RCube A and B, and connected together (fig.7.3) is describe thereafter.
- 1.
- Just after nreset and nreset_link[i]i=0..7 are released on a Rcube, every HSL link
is reseted for 4096 ckin clock cycles. Every sdout0..7 is forced at à 0.
- 2.
- Then ,the serializer calibration phase lasts for 4096 ckin clock cycles. Every sdout0..7
is forced at à 0.
- 3.
- After that the serializer must be calibrated. The sdout0..7 outputs are validated and
begin emitting IDLE characters in order to calibrate the deserializer they are connected to.
- 4.
- Every deserializer receives IDLE characters. After a period that lasts at least 3000 recovered clock
cycles, the deserializer is also calibrated.
- 5.
- Finally, a protocol based on the exchange of request and acknowledge control characters
is used to test the good synchronisation between the two serial macrocell A and B.
When this last phase is over, the signal linkstatus[i](i=0..7) goes high indicating
that the serial link[i] is working.
When the links are functional, RCUBE automatically sends on every link, two flow control characters FCC
(spaced of 8 cycles) to inform the others devices that it is ready to receive two flits.
WARNING : when a device wants to inform RCUBE that it can receive two flits, it must
space the sending of the two FCC characters by at least 4 cycles.
Next: 8.ERROR DETECTION
Up: The MPC project
Previous: Serial macrocell
