Sundance SMT148 - Manual (Page 26)

Version 1.4 Page 26 of 35 SMT148 User Manual
Status register
Bit 29 down to 28: Transfer type to microcontroller
RS232=”00”, RS485=”01”, USB=”10”, Firewire=”11”
Bit 9: Busy signal, active high. It indicates that the data path to the switch fabric is
busy with a transfer from the microcontroller. A new transfer from the microcontroller
cannot be started until this signal has been de-asserted.
Bit 8: FIFO to Switch Fabric almost full => the microcontroller should stop writing data
to the interface and wait for this flag to be low again before continuing the transfer.
Bit 7 down to 0: Number of words in the FIFO to the microcontroller (FIFO is 1024
words deep) => the microcontroller can start reading data with a maximum burst size
of this number.
Destination register
This register contains the address of the destination connected to the switch fabric
when the microcontroller does not know where to send the words it will transmit (i.e.,
when the microcontroller tries to access a node with address 255). The default value
of this register is h40000000 (ComPort 0). This register can be written or read by the
microcontroller using register addresses (Table 17). This register can also be written
by any node connected to the switch fabric (e.g., ComPorts) when sending the
following word to the microcontroller interface.
Bit 30: must be 1
Bit 7 downto 0: Address of the destination node
Firmware revision number
The firmware revision number can be accessed by the microcontroller in order to
check what are the version of the current firmware as well as the size of the FPGA.
The firmware revision number is coded on 8 bits.
Bit 31 down to 8: reserved
Bit 7 down to 5: a, revision number “before comma”
Bit 4 down to 2: b, revision number “after comma”
Bit 1 down to 0: c, FPGA size , 00=> VP7