Programmable arbitrary sequence direct memory access controller for configuring multiple core independent peripherals
View Patent ↗A programmable arbitrary sequence direct memory access (DMA) controller accesses sequentially addressed memory locations (source or destination) using address pointer registers. Each sequentially addressed memory location containing an indirect memory address is stored in an address latch and used to access the actual non-sequential memory location to be accessed by the DMA transfer.
1. A programmable arbitrary sequence direct memory access (DMA) controller, comprising:
a first address pointer register storing a first source address wherein the first source address is an address within a memory space accessible by the programmable arbitrary sequence DMA controller;
a second address pointer register storing a first destination address wherein the first destination address is an address within the memory space;
a data latch coupled to a first data bus storing data from the first source address;
an address latch coupled to a second data bus storing a second source address or a second destination address, wherein the second source address or the second destination address is an address within the memory space;
a multiplexer having a first input coupled to the first address pointer register, a second input coupled to the address latch, a third input coupled to the second address pointer register, and an output coupled to an address bus;
control logic coupled to and controlling the first and second address pointer registers, the address latch, the multiplexer and the data latch, wherein the programmable arbitrary sequence DMA controller transfers data from a source to a destination wherein the control logic of the programmable arbitrary sequence DMA controller is configured to store data from the first source address or the second source address in the data latch and thereafter transfer the data from the data latch to the first destination address or the second destination address, and
a control register configured to control an operating mode of the DMA controller, wherein when operating in a first mode, the DMA controller is configured to use the first address pointer register for storing the first source address and the second address pointer register for storing the first destination address, and when operating in a second mode, the DMA controller is configured to receive the second source address or the second destination address in the address latch from the second data bus.
2. The programmable arbitrary sequence DMA controller according to claim 1 , wherein one bit in the control register determines whether the DMA controller operates in the first or second mode.
3. The programmable arbitrary sequence DMA controller according to claim 1 , wherein the control logic communicates with bus arbitration logic.
4. The programmable arbitrary sequence DMA controller according to claim 1 , wherein the data latch writes to and reads from the first data bus.
5. The programmable arbitrary sequence DMA controller according to claim 1 , wherein the first data bus is coupled to a data memory.
6. The programmable arbitrary sequence DMA controller according to claim 5 , wherein the data memory is a random-access memory (RAM).
7. The programmable arbitrary sequence DMA controller according to claim 1 , wherein the second data bus is coupled to a program memory.
8. The programmable arbitrary sequence DMA controller according to claim 7 , wherein the program memory is a non-volatile memory.
9. The programmable arbitrary sequence DMA controller according to claim 8 , wherein the non-volatile memory is a flash programmable memory.
10. The programmable arbitrary sequence DMA controller according to claim 1 , wherein the first and second data buses are each coupled to a memory.
11. The programmable arbitrary sequence DMA controller according to claim 1 , further comprising first and second byte counters communicating with the control logic and counting a number of data bytes transferred.
12. A method for indirect memory addressing with a programmable arbitrary sequence direct memory access (DMA) controller configured to transfer data within a memory space, said method comprising the steps of:
determining an operating mode from a control register configured to control an operating mode of the DMA controller;
wherein when operating in a first mode:
for performing a DMA transfer, using a first address pointer register for storing a first source address and a second address pointer register for storing a first destination address;
and when operating in a second mode:
reading a register address stored at a memory address specified by the first address pointer register, wherein the memory address is an address within the memory space accessible by the programmable arbitrary sequence DMA controller;
storing the register address in an address latch;
reading configuration data stored at another memory address specified by the second address pointer register, wherein the another memory address is an address within the memory space;
storing the configuration data in a data latch; and
writing the configuration data stored in the data latch to a register at the register address stored in the address latch.
13. The method according to claim 12 , wherein the register is a peripheral register.
14. The method according to claim 13 , wherein the peripheral register is a special function register.
15. The method according to claim 14 , wherein the special function register is associated with a core independent peripheral (CIP).
16. The method according to claim 12 , further comprising the step of coupling the data latch to a first data bus and data memory.
17. The method according to claim 12 , further comprising the step of coupling the address latch to a second data bus and program memory.
18. The method according to claim 12 , wherein the DMA controller is configurable to operate in a direct addressing mode in which the first address pointer register stores a source address and the second address pointer register stores a destination address.
19. A method for indirect memory addressing with a programmable arbitrary sequence direct memory access (DMA) controller configured to transfer data within a memory space, said method comprising the steps of:
determining an operating mode from a control register configured to control an operating mode of the DMA controller;
wherein when operating in a first mode:
for performing a DMA transfer, using a first address pointer register for storing a first source address and a second address pointer register for storing a first destination address;
and when operating in a second mode:
reading a register address stored at a first memory address specified by the first address pointer register, wherein the first memory address is an address within a memory space accessible by the programmable arbitrary sequence DMA controller;
storing the register address in an address latch;
reading configuration data stored in a peripheral register having a second memory address specified by the register address in the address latch wherein the second address is an address within the memory space;
storing the configuration data in a data latch; and
writing the configuration data to a memory at an address specified by the second address pointer register.
20. The method according to claim 19 , wherein the register is a peripheral register.
21. The method according to claim 20 , wherein the peripheral register is a special function register.
22. The method according to claim 21 , wherein the special function register is associated with a core independent peripheral (CIP).
23. The method according to claim 19 , further comprising the step of coupling the data latch to a first data bus and data memory.
24. The method according to claim 19 , further comprising the step of coupling the address latch to a second data bus and program memory.
25. The method according to claim 19 , wherein the DMA controller is configurable to operate in a direct addressing mode in which the first address pointer register stores a source address and the second address pointer register stores a destination address.