ADC sequencing
A device comprises a central processing unit (CPU) and a memory configured for storing memory descriptors. The device also includes an analog-to-digital converter controller (ADC controller) configured for managing an analog-to-digital converter (ADC) using the memory descriptors. In addition, the device includes a direct memory access system (DMA system) configured for autonomously sequencing conversion operations performed by the ADC without CPU intervention by transferring the memory descriptors directly between the memory and the ADC controller for controlling the conversion operations performed by the ADC.
1. A device comprising:
a central processing unit (CPU);
a memory configured for storing memory descriptors;
an analog-to-digital converter controller (ADC controller) configured for managing an analog-to-digital converter (ADC) using the memory descriptors; and
a direct memory access (DMA) system configured for autonomously sequencing conversion operations performed by the ADC without CPU intervention by transferring the memory descriptors directly between the memory and the ADC controller for controlling the conversion operations performed by the ADC,
wherein the ADC controller is configured for setting parameters for conversion operations performed by the ADC based on information included in the memory descriptors received from the DMA system, and wherein the information included in the memory descriptors are configured independent of the CPU.
2. The device of claim 1 , wherein the CPU is configured to be idle or performing reduced activities at a time when conversion operations are performed by the ADC.
3. The device of claim 2 , wherein CPU is configured to be performing activities unrelated to the ADC at the time when the conversion operations are performed by the ADC.
4. The device of claim 1 , wherein the memory descriptors in the memory are managed by the DMA system, and
wherein the ADC controller is not directly coupled to the memory.
5. The device of claim 1 , wherein the memory descriptors received from the DMA system at the ADC controller comprise information on per-channel settings for conversion operations performed by the ADC, wherein a channel is associated with an input pin of the ADC.
6. The device of claim 5 , wherein the information included in the memory descriptors are arranged as bit fields that comprise amplification gain, gain compensation, single-ended or bipolar operating mode, channel polarity and selection of negative and positive channels of the ADC.
7. The device of claim 1 , wherein the ADC controller includes a first register configured for storing parameters for a conversion operation performed by the ADC, and wherein the ADC controller is operable to:
receive a memory descriptor from the DMA system via a peripheral data bus;
extract, from the memory descriptor, information on a conversion operation to be performed by the ADC; and
map the extracted information to the first register.
8. The device of claim 7 , wherein the information included in a memory descriptor received from the DMA system corresponds to one conversion operation performed by the ADC.
9. The device of claim 7 , wherein the ADC controller includes a second register configured for storing a result of a conversion operation performed by the ADC, and
wherein the ADC controller is operable to generate a signal indicating that the conversion operation performed by the ADC is completed.
10. The device of claim 9 , wherein the result of the conversion operation performed by the ADC is transferred from the second register to the memory using a memory descriptor, and wherein the DMA system is operable to:
receive, from the ADC controller, the signal indicating that the conversion operation performed by the ADC is completed; and
in response to receiving the signal, transfer the result of the conversion operation from the second register to the memory using the memory descriptor.
11. The device of claim 1 , wherein the DMA system is configured for autonomously sequencing conversion operations performed by an additional peripheral hardware without CPU intervention by transferring the memory descriptors directly between the memory and a controller managing the additional peripheral hardware.
12. The device of claim 1 , wherein the DMA system is configured for transferring memory descriptors to the ADC controller in response to receiving a ready signal from the ADC controller.
13. The device of claim 12 , wherein a ready signal is uniquely associated with a single transfer cycle.
14. The device of claim 13 , wherein the DMA system is configured for transferring a single memory descriptor in one transfer cycle.
15. The device of claim 1 , wherein a number of conversion operations performed by the ADC is limited by a number of the memory descriptors stored in the memory.
16. The device of claim 1 , wherein an order of the conversion operations performed by the ADC is based on an arrangement of the memory descriptors in the memory.
17. The device of claim 1 , wherein a size of a memory descriptor is 32 bit, 64 bit or 128 bit.
18. A method comprising:
accessing, by a direct memory access (DMA) system, a first memory descriptor stored in a memory that include information on parameter settings for a first operation performed by a peripheral hardware module, wherein information included in memory descriptors stored in the memory are configured independent of a central processing unit (CPU) associated with the DMA system, and wherein the accessing is performed by the DMA without CPU intervention;
transferring, by the DMA system, the first memory descriptor to a controller associated with the peripheral hardware module, wherein the information included in the first memory descriptor is stored in a first register associated with the controller, and wherein the transferring is performed by the DMA without CPU intervention;
receiving, at the DMA system, a signal from the controller indicating that the first operation performed by the peripheral hardware module managed is completed;
in response to receiving the signal:
transferring, by the DMA system, a result of the first operation from a second register associated with the controller to the memory using the first memory descriptor, wherein the transferring is performed by the DMA without CPU intervention;
accessing, by the DMA system, a second memory descriptor stored in the memory that include information on parameter settings for a second operation performed by the peripheral hardware module; and
transferring, by the DMA system, the second memory descriptor to the controller, wherein the information included in the second memory descriptor is stored in the first register associated with the controller.
19. The method of claim 18 , comprising:
receiving, by the controller, the first memory descriptor from the DMA system;
extracting, by the controller and from the first memory descriptor, information on the first operation to be performed by the peripheral hardware module;
storing, by the controller, the extracted information about the first operation in the first register;
configuring, by the controller, the peripheral hardware module to perform the first operation based on the information stored in the first register;
storing, by the controller, result of the first operation in the second register; and
generating, by the controller, the signal indicating that the first operation performed by the peripheral hardware module is completed.
20. The method of claim 19 , wherein the information included in the first memory descriptor is arranged as bit fields, and wherein storing the extracted information about the first operation in the first register comprises:
mapping, by the controller, the extracted information to corresponding bit fields the first register.