Cirrus Logic Inc.

Ashutosh S Dikshit

Stephen A Smith

Daniel G Bezzant

Narasimha R Nookala

Jihad Y Abudayyeh

Arunachalam Vaidyanathan

Puducode S Narayanan

A PCMCIA host adapter includes the capability to master a non-DMA system bus and control a DMA data transfer between a DMA capable peripheral and the internal system memory. A peripheral can be coupled to the system through a PCMCIA card plugged into a PCMCIA expansion slot. A DMA controller coupled to the PCMCIA expansion slots through a PCMCIA bus controls a DMA transfer between the internal system memory and the peripheral. A bus master disables the CPU and takes control of the system bus during a DMA data transfer. In an alternative embodiment, the PCMCIA host adapter can be used with either a system having a system bus with DMA capability or with a system having a system bus without DMA capability. In this alternate embodiment if the system bus has DMA capability, the PCMCIA host adapter effectively passes the DMA signals between the peripheral and the system bus. If the system bus does not have DMA capability then the DMA controller and the bus master work to disable the CPU and take control of the system bus during a DMA data transfer. The DMA controller then controls the transfer of data between the peripheral and the internal system memory.

PCMCIA host adapter and method for variable data transfers

An apparatus for providing register compatibility between integrated circuits having different register and interrupt configurations is designed to operate with software that was written for previous hardware. Versions of software written for previous hardware attempt non-native register accesses for which the integrated circuit is designed to emulate the non-native register set. Versions of software specifically written for the present hardware attempt native register accesses for which no emulation is necessary. In the preferred embodiment only one physical register set is included on the integrated circuit and a compatibility engine is used when a non-native register access is attempted. The compatibility engine is coupled between a bus interface unit and the physical register set and allows a user or system designer to address a register set of another integrated circuit having a different configuration than the physical register set. The compatibility engine converts the address and maps the data bits of the emulated register into registers within the physical register set. Alternatively, two sets of registers can be physically included on the integrated circuit. An interrupt compatibility circuit is also designed to operate in at least a first mode or a second mode. In the first mode the interrupt information is written to an appropriate register and then mapped into the appropriate bits of the physical register set. In the second mode the interrupt information is written directly to the appropriate register. In both the first and second modes, steering bits from the appropriate register are used to map system, management and wakeup interrupts to the appropriate interrupt pad where the interrupt request signal is then shaped.

Method and apparatus for providing register and interrupt compatibility

An apparatus for providing register compatibility between integrated circuits having different register and interrupt configurations is designed to operate with software. Software may attempt non-native register accesses; the integrated circuit of the present invention will emulate a non-native register set. In the preferred embodiment only one physical register set is included on the integrated circuit and a compatibility engine is used when a non-native register access is attempted. The compatibility engine is coupled between a bus interface unit and the physical register set and allows a user or system designer to address a register set of another integrated circuit having a different configuration than the physical register set. The compatibility engine converts the address and maps the data bits of the emulated register into registers within the physical register set. Alternatively, two sets of registers can be physically included on the integrated circuit. An interrupt compatibility circuit is also designed to operate in at least a first mode or a second mode. In the first mode, the interrupt information is written to an appropriate register and then mapped into appropriate bits of the physical register set. In the second mode, interrupt information is written directly to the appropriate register.

Growing community of inventors

Mountain View, CA, United States of America

Ashutosh S Dikshit