Special consideration should be given to handling interrupts when using extended addressing on the Texas Instruments (TI) TMS320C54x family of digital signal processing devices. Because extended addressing uses up to 23 address lines on a 16-bit device, the user must account for saving and restoring the extended address values. This operation is handled automatically when using the far instructions. However, when dealing with interrupts, no assumptions can be made on the part of the architecture as to whether you are actually utilizing the extended memory capabilities of the device. Therefore, only the 16-bit “local” address is automatically saved on the stack on acknowledging an interrupt.
This document covers available options for handling interrupt service routines (ISRs) when using the extended addressing capability of the TMS320C54x. Included in this document are code examples and memory configuration options.……