Slave and a master device, a system incorporating the devices, and a method of operating the slave device
An electronic slave device includes a hardware data packing block having a configurable multiplexing unit having inputs connected to system bus, wires for receiving in parallel each bit of a data word, outputs connected to the respective data write pins of a memory for outputting in parallel each bit of a rearranged data word to be recorded, and rearrangeable connections between the inputs and the outputs according to a set configuration; a format register, the value of which can be set by an external master device to at least two different values; and a logic circuit capable of setting the connections of the multiplexing unit according to the value of the format register to obtain a rearranged data word having at least one symbol with a shifted position in comparison with the position of this symbol in the received data word.
1. An electronic slave device to receive P-bit width symbols transmitted from an external master device X symbols being placed within a N-bit width dataword which is transmitted all at once from the master device to the slave device through a system bus, the slave device comprising:
a writeable memory,
a hardware data packing block comprising a configurable multiplexing unit having inputs connected to the system bus wires to receive in parallel each bit of the dataword, outputs connected to the respective data write pins of the memory to output in parallel each bit of a rearranged dataword to be recorded, and rearrangeable connections between the inputs and the outputs according to a set configuration,
a format register for storing a transport format value, the value of which can be set by the external master device to at least two different values, and
a logic circuit capable of setting the connections of the multiplexing unit according to the value of the format register to obtain a rearranged dataword having at least two symbols with at least one symbol with a shifted position by comparison to the position of this symbol in the received dataword, said rearranged dataword having a data occupation that is defined by said transport format value.
2. The slave device according to claim 1 , wherein the writeable memory is a bit addressable memory having K-bit width addressable rows, each row being divided into a plurality of P-bit width cells, K being a positive integer, and wherein the logic circuit is able to set the connection of the multiplexing unit for each received dataword to:
record the X symbols placed within a first received dataword in P-bit width cells of the memory so that at least one free P-bit width cell remains on one of the addressable row used to record these symbols, and
record at least one of the symbols placed within a second dataword in the free cell of the addressable row previously used to record symbols of the first dataword in order to complete this row.
3. The slave device according to claim 2 , wherein the hardware data packing block is designed to record each symbol in each addressable row according to a predetermined order in which the symbols are transmitted from the master device to the slave device.
4. A master device to transmit P-bit width symbols to a slave device according to claim 1 , X symbols being placed within a N-bit width dataword which is transmitted all at once from the master device to the slave device through a system bus, wherein the master device is able to set the format register value of the slave device.
5. A system to transmit P-bit width symbols from an external master device to a slave device, X symbol being placed within a N-bit width dataword which is transmitted all at once from the master device to the slave device through a system bus, the system comprising:
the master device,
the slave device, and
the system bus,
wherein the slave device comprises the electronic slave device of claim 1 .
6. A method to operate a slave device according to claim 1 , wherein the method comprises the step of setting the connections of the multiplexing unit according to the value of the format register to obtain a rearranged dataword having at least one symbol with a shifted position by comparison of the position of this symbol in the received dataword.
7. A method according to claim 6 , wherein the method comprises:
a first recording step during which the X symbols placed within the first received dataword are recorded in a P-bit width cells of the memory so that at least one free P-bit width cell remains on one of the addressable row used to record these symbols, and
a second recording step during which at least one of the symbols placed within a second received dataword is recorded in the free cell of the addressable row previously used to record symbols of the first dataword in order to complete this row.
8. The method according to claim 7 , wherein during the first and second recording steps, the symbols in each addressable row are recording according to a predetermined order in which the symbols are transmitted from the master device to the slave device.