Camera control interface slave device to slave device communication
First Claim
1. A master device, comprising:
- a bus interface circuit to couple to a control data bus shared with a plurality of slave devices; and
a processing circuit coupled to the bus interface circuit and configured to;
control access to the control data bus by the plurality of slave devices;
receive a slave device to slave device communication request from a slave device requesting access to the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, and wherein the slave device to slave device communication request includes a requested maximum number of words to be transferred from the requesting slave device to another slave device over the control data bus; and
send, to the requesting slave device, a response granting the request, wherein the response grants the request by including a word limit number in the response that is equal to or greater than a maximum number of words specified in the request.
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Accused Products
Abstract
In a shared bus where communications are managed by a master device, direct slave device to slave device (S2S) communications is implemented. A first slave device wanting to communicate with a second slave device may make a S2S communication request to the master device. The request may include a requested number of words that the first slave device wishes to send over the shared bus. The master device may have a current word limit which may vary based upon operating parameters. The master device may deny the request if the requested number of words is greater than the current word limit or if it does not support S2S communications. Denial of the request may also be for other reasons, like activity over the shared bus. If the master device grants the request, the slave device may send the requested number of words to another slave device over the shared bus.
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Citations
20 Claims
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1. A master device, comprising:
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a bus interface circuit to couple to a control data bus shared with a plurality of slave devices; and a processing circuit coupled to the bus interface circuit and configured to; control access to the control data bus by the plurality of slave devices; receive a slave device to slave device communication request from a slave device requesting access to the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, and wherein the slave device to slave device communication request includes a requested maximum number of words to be transferred from the requesting slave device to another slave device over the control data bus; and send, to the requesting slave device, a response granting the request, wherein the response grants the request by including a word limit number in the response that is equal to or greater than a maximum number of words specified in the request. - View Dependent Claims (2, 3)
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4. A master device, comprising:
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a bus interface circuit to couple to a control data bus shared with a plurality of slave devices; and a processing circuit coupled to the bus interface circuit and configured to; control access to the control data bus by the plurality of slave devices; receive a slave device to slave device communication request from a slave device requesting access to the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, wherein the slave device to slave device communication request includes a requested maximum number of words to be transferred from the requesting slave device to another slave device over the control data bus; and send, to the requesting slave device, a response denying the request, wherein the slave device to slave device communication request is denied if the requested maximum number of words is greater than a current word limit of the master device. - View Dependent Claims (5, 6)
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7. A method operational by a master device, comprising:
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controlling access to a control data bus shared with a plurality of slave devices; receiving a slave device to slave device communication request from a slave device requesting access to the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, wherein the slave device to slave device communication request includes a requested maximum number of words to be transferred from the requesting slave device to another slave device over the control data bus; and sending, to the requesting slave device, a response denying the request, wherein the response denying the request includes an acceptable number of words that is less than the requested maximum number of words. - View Dependent Claims (8, 9, 10)
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11. A slave device, comprising:
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a bus interface circuit to couple to a control data bus shared with a plurality of slave devices and at least one master device; a processing circuit coupled to the bus interface circuit and configured to; send a slave device to slave device communication request from the slave device to the master device over the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, wherein the communication request indicates a requested maximum number of words to be transmitted by the slave device to another slave device over the control data bus; and receive a response denying the request from the master device, wherein the response indicates an acceptable maximum number of words from the master device. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method operational on a slave device, comprising:
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coupling the slave device to a control data bus shared with a plurality of slave devices and at least one master device; sending a slave device to slave device communication request from the slave device to the master device over the control data bus, wherein the slave device to slave device communication request is for a direct data transfer between the slave device and another slave device of the plurality of slave devices while bypassing the master device, wherein the slave device to slave device communication request includes a requested number of words to be transferred by the slave device to another device over the control data bus; and receiving from the master device, a response granting the request, wherein the response grants the request by including a word limit number in the response that is equal to or greater than the requested number of words included in the slave device to slave device communication request. - View Dependent Claims (19, 20)
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Specification