XS1-L02A-QF124-I5 XMOS, XS1-L02A-QF124-I5 Datasheet - Page 13

• Manufacturer Part Number: XS1-L02A-QF124-I5
• Description: IC MPU 32BIT DUAL CORE 124QFN
• Manufacturer: XMOS

Specifications of XS1-L02A-QF124-I5

• Processor Type: XCore 32-Bit
• Speed: 500MHz
• Voltage: 0.95 V ~ 1.05 V
• Mounting Type: Surface Mount
• Package / Case: 124-TFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 880-1031

XMOS
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mits a HELLO. On reception of a HELLO, the receiving LLink resets its credits-
issued counter, and issues at least eight credits. This sets the credits-issued
counter to eight and transmits a CREDITX . On reception of a CREDITX , the
receiving LLink increments its credit-counter by X .
When asked to RESET, a LLink resets the shift register capturing a token, clear-
ing out any half tokens that may have been received.
3.2.1 Credits
The standard mode of operation is that a switch can issue credits on a link -
when it does so, the switch allows the transmitter on the remote end of the link
to transmit data to this switch.
The switch specifies how much credit is issued (8 to 64 bytes) using the reserved
control tokens CREDIT8, CREDIT16 and CREDIT64. The transmitter will not
transmit more tokens then there are credits. When multiple credit messages are
issued, credits are summed together at the transmitting side; a transmitter must
have a credit counter of at least 7 bits. Hence, it is illegal to send two subsequent
CREDIT64 tokens, but legal to send a second CREDIT64 when one token has
been received.
A transmitter should issue credits to the receiver, if it knows that the receiver is
running low on credits, and if there is space in its input buffer. To save bandwidth,
the transmitter should try and issue the largest possible credit token.
All data tokens require and consume credits. Most control tokens require and
consume credits when transmitted, the exceptions are CREDITn, HELLO, and
RTNZn; these tokens can be transmitted when there are no credits present be-
cause the link layer interprets them and does not insert them into the buffer. The
application level tokens END and PAUSE consume credits as usual since they
do end up in the buffer.
An enabled link is initialised by requesting it to send a HELLO token. This re-
quest can come from a local processor, or from a remote processor; possibly
even over the link itself. HELLO signals that this side is ready to receive credits.
It requests that the other side clears its “issued-counter”, and issues credits.
NOTE: The HELLO token is not compatible with the XS1-G.
The definition of the three hardware control tokens used at the link layer is:
XS1-L S
S
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YSTEM
PECIFICATION