Method of communication for master device and slave device on synchronous data bus wherein master and slave devices are coupled in parallel
Some embodiments include a method of communication between a master device and N slave devices on a synchronous data bus. The method includes selecting a slave device from among the N slave devices using a selection channel, where the master device and the N slave devices are coupled in series through the selection channel. The method also includes transmitting data between the master device and the selected slave device using a transmission channel, where the master device and the N slave devices are coupled in parallel through the transmission channel.
1. A device comprising:
a bus interface of the serial peripheral interface bus (SPI) type, the bus interface comprising:
a clock terminal configured to be coupled to a clock line,
a master-output-slave-input (MOSI) node,
a master-input-slave-output (MISO) terminal configured to be coupled in parallel to N slave devices, wherein N is a positive integer greater than 1, and
a mode selection terminal configured to be coupled in parallel to the N slave devices;
a first MOSI terminal configured to be coupled in series to the N slave devices;
a second MOSI terminal configured to be coupled to be coupled in parallel to the N slave devices; and
an output-input switch coupled between the MOSI node and the first and second MOSI terminals, wherein the output-input switch is configured to link the MOSI node to one or the other of the first and second MOSI terminals.
2. The device of claim 1 , wherein the device is configured to generate a first slave configuration command to place the N slave devices in a serial mode using the mode selection terminal.
3. The device of claim 1 , wherein the device is configured to, during a selection step,
generate a first slave configuration command to place the N slave devices in a serial mode using the mode selection terminal;
link the MOSI node to the first MOSI terminal using the output-input switch; and
select a slave device from among the N slave devices using the first MOSI terminal.
4. The device of claim 3 , wherein the device is configured to generate a second slave configuration command to place the selected slave device in a parallel mode using the mode selection terminal.
5. The device of claim 3 , wherein the device is configured to receive, during the selection step, respective slave identification data from each of the N slave devices, wherein the respective slave identification data comprises respective maximum clock signal frequency supported by each of the N slave devices.
6. The device of claim 5 , wherein the device is configured to generate a clock signal on the clock line at the a frequency that is the smallest of the maximum clock signal frequencies received from the N slave devices.
7. The device of claim 3 , wherein, during the selection step, the device is configured to enumerate the N slave devices.
8. The device of claim 1 , wherein the device is configured to detect a presence signal from a slave device of the N slave devices using the first MOSI terminal during an end-of-chain detection step.
9. The device of claim 8 , wherein the device is configured to detect hot connection or disconnection of a slave device of the N slave devices by periodically performing the end-of-chain detection step.
10. The device of claim 1 , wherein the device is configured to generate a clock signal on the clock line to regulate exchanges and transmissions of data between the device and the N slave devices.
11. A device comprising:
a bus interface of the serial peripheral interface bus (SPI) type, the bus interface comprising:
a clock terminal configured to receive a clock signal from a master device,
a master-output-slave-input (MOSI) node,
a master-input-slave-output (MISO) node, and
a mode selection terminal configured to place the device in serial mode or parallel mode;
a first MOSI terminal configured to be coupled to the master device;
a second MOSI terminal configured to be coupled to the master device and to N−1 slave devices, wherein N is a positive integer greater than 1;
an output-input switch coupled between the MOSI node and the first and second MOSI terminals, wherein the output-input switch is configured to link the MOSI node to one or the other of the first and second MOSI terminals;
a first MISO terminal configured to be coupled to a slave device of the N−1 slave devices;
a second MISO terminal configured to be coupled to the master device and to the N−1 slave devices; and
an input-output switch coupled between the MISO node and the first and second MISO terminals, wherein the input-output switch is configured to link the MISO node to one or the other of the first and second MISO terminals.
12. The device of claim 11 , wherein the device is configured to transmit a slave identification data comprising a maximum clock signal frequency when the mode selection terminal places the device in serial mode.
13. The device of claim 11 , wherein the device is configured to detect, during a detection step, a presence signal from the slave device of the N−1 slave devices using the first MISO terminal.
14. The device of claim 13 , wherein the device is configure to, during the detection step, apply a pull voltage to the first MISO terminal and apply a reset voltage to the first MOSI terminal.
15. The device of claim 11 , wherein the mode selection terminal is configured to be coupled to the master device and to the N−1 slave devices.
16. The device of claim 11 , wherein the first MOSI terminal configured to be coupled to the master device via a slave device of the N−1 slave devices.
17. A device configured to be coupled to a synchronous data bus, the device comprising:
a clock terminal configured to be coupled to a clock line,
a master-output-slave-input (MOSI) node,
a master-input-slave-output (MISO) terminal configured to be coupled in parallel to N slave devices, wherein N is a positive integer greater than 1, and
a mode selection terminal configured to be coupled in parallel to the N slave devices;
a first MOSI terminal configured to be coupled in series to the N slave devices;
a second MOSI terminal configured to be coupled to be coupled in parallel to the N slave devices; and
an output-input switch coupled between the MOSI node and the first and second MOSI terminals, wherein the output-input switch is configured to link the MOSI node to one or the other of the first and second MOSI terminals, and wherein the device is configured to:
select a slave device from among the N slave devices using the first MOSI terminal when the mode selection terminal is in a first state, and
transmit data to the selected slave device using the second MOSI terminal when the mode selection terminal is in a second state different from the first state.
18. The device of claim 17 , wherein the device is configured to generate a clock signal on the clock line to regulate exchanges and transmissions of data between the device and the N slave devices.
19. The device of claim 18 , wherein the device is configured to generate commands, communications and transmissions of data using the clock terminal, the MISO terminal, and the second MOSI terminal, in accordance to a serial peripheral interface bus (SPI) protocol type.
20. The device of claim 17 , wherein the device is configured to detect a presence signal from a slave device of the N slave devices using the first MOSI terminal during a detection step.