[linux-dvb] Re: [RFC] USB DVB design | state machine overview

[Holger Waechtler <holger@convergence.de>]

here just a short outline how the firmware is supposed to work:

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in order to start a transaction the onchip 8051 does something like this

  - initializes the transaction count register = 188
  - start the GPIF state machine, state 1

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GPIF state 1

  - wait until pin RDY0 (signal TSSYNC) goes high + INTRDY
     (sync byte 0x47 is received and we have space in the FIFO)
  - go to state 2

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GPIF state 2

  - wait for RDY1 (signal TSCLK) going low
  - go to state 3

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GPIF state 3

  - wait for RDY1 (signal TSCLK) going high
  - sample current data byte, write it into FIFO
  - if transaction count > 0 go to state 2, elso go idle
     and throw done_irq

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on done_irq the 8051 can take a look on the PID bytes in the packets:

  - look up in the PID table if we're interested in this PID
  - if so: pass this packet to the host PC, else skip this packet
  - swap FIFO pages
  - start transaction again

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