Serial peripheral interface daisy chain mode system and apparatus
First Claim
1. An apparatus for entering daisy-chain mode in an SPI device comprising:
- an input to receive serial data;
a clock pin to receive a temporal signal;
a select pin; and
,a serial output whose default instruction is a signal to enable daisy chain mode within 16 clock cycles, which is implemented at startup;
wherein, the SPI device is configured to change between daisy chain mode and a register addressable mode in response to the assertion of the select pin.
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Accused Products
Abstract
SPI frame for simultaneously entering 8 bit daisy-chain mode from 16 bit register addressable mode. Some products that implement SPI may be connected in a daisy chain configuration, the first slave output being connected to the second slave input, etc. The SPI port of each slave is designed to send out during the second group of clock pulses an exact copy of the data it received during the first group of clock pulses. The whole chain acts as a communication shift register; daisy chaining is often done with shift registers to provide a bank of inputs or outputs through SPI. Large latency occurs during the entry into daisy-chain mode which increases as a function of the number of linked SPI devices. A means for simultaneously instructing all connected devices to enter/enable daisy-chain mode is disclosed.
7 Citations
24 Claims
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1. An apparatus for entering daisy-chain mode in an SPI device comprising:
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an input to receive serial data; a clock pin to receive a temporal signal; a select pin; and
,a serial output whose default instruction is a signal to enable daisy chain mode within 16 clock cycles, which is implemented at startup; wherein, the SPI device is configured to change between daisy chain mode and a register addressable mode in response to the assertion of the select pin. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for entering daisy-chain mode comprising:
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an SPI master device; and
,a plurality of SPI slave devices concatenated in a daisy chain configuration, each SPI slave device comprises; an input to receive serial data; a clock pin to receive a temporal signal; a select pin; and
,a serial output whose default instruction is a signal to enable daisy chain mode within 16 clock cycles, which is implemented at startup; wherein, the SPI device is configured to change between daisy chain mode and a register addressable mode in response to concurrently receiving a predetermined pattern on the clock pin and predetermined pulses on the select pin. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. An apparatus for entering daisy-chain mode in an SPI device comprising:
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a means for receiving serial data; a means for receiving a clock signal; a means for receiving a select signal; and
,a means for transmitting serial output, wherein the default transmission is a signal to enable daisy chain mode within 16 clock cycles which is implemented at startup; wherein, the SPI device is configured to change between daisy chain mode and a register addressable mode in response to the assertion of the means for receiving a select signal.
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20. A system for entering daisy-chain mode in a plurality of serial peripheral devices within a single serial frame and dynamically change the plurality of Serial Peripheral Devices (SPD) from register addressable mode to daisy-chain mode in a single serial frame, the system comprising:
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a plurality of serial peripheral devices comprising a select pin and serial device output (SDO) in a daisy chain configuration, wherein the plurality of serial peripheral devices initializes into register addressable mode after any powerup; wherein, the serial device output default instruction is a signal to enable daisy chain mode within 16 clock cycles which is outputted to the next serial peripheral device in the system; whereby, the serial device output default instruction is automatically clocked to the next device in the chain on the first single serial frame, after the select pin is asserted. - View Dependent Claims (21, 22, 23, 24)
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Specification