Single chip microcontroller having down-loadable memory organization supporting "shadow" personality, optimized for bi-directional data transfers over a communication channel
First Claim
1. A microcontroller integrated circuit for connecting a computer system having a host processor to an ISDN interface to accommodate data transfer over an ISDN network, comprising:
- a local processor; and
a dual port RAM addressable by the host processor and said local processor and having a predetermined first memory space for storing program code and a predetermined second memory space for storing data,whereby the host processor and said local processor can simultaneously access said second memory space and the host processor can further access said first and second memory spaces when it resets said local processor while said local processor is in reset and when said local processor is not in reset, said local processor can access said first and second memory spaces.
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Accused Products
Abstract
A microcontroller down-loadable memory organization supporting "shadow" personality, optimized for connecting a computer system to an ISDN network to facilitate transmitting and receiving of data, the microcontroller including a processor and a memory structure having ROM memory space for storing program code therein and further including a dual port RAM for connection between the computer and the processor, the dual port RAM having RAM memory space for storing program code therein and shared RAM for storing data capable of being simultaneously accessible by the processor and the computer, wherein the program ROM and the program RAM are selectively used by the computer to store program code by the computer using a ROM/RAM* select signal, and wherein the starting address in the shared RAM wherein data is stored is selectably offset from the starting address of the code RAM and the code ROM.
107 Citations
17 Claims
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1. A microcontroller integrated circuit for connecting a computer system having a host processor to an ISDN interface to accommodate data transfer over an ISDN network, comprising:
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a local processor; and a dual port RAM addressable by the host processor and said local processor and having a predetermined first memory space for storing program code and a predetermined second memory space for storing data, whereby the host processor and said local processor can simultaneously access said second memory space and the host processor can further access said first and second memory spaces when it resets said local processor while said local processor is in reset and when said local processor is not in reset, said local processor can access said first and second memory spaces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A microcontroller for facilitating transfer of digital information from a host processor through a communication channel, comprising:
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a local processor; a program ROM having storage locations addressable by said local processor, said program ROM for storing program code; a dual port RAM having storage locations addressable by the host processor and said local processor and having a predetermined storage area for storing data, said data storage area being simultaneously accessible by the local processor and the host processor, whereby the host processor and said local processor can simultaneously access said data storage area and the host processor can further access said program storage area and said data storage when said local processor is in reset, and when said local processor is not in reset, said local processor can access said data storage space and said program storage space. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification