Do you mean the ARM7TDMI? The reference manual for the ARM7TDMI can be found [url="http://infocenter.arm.com/help/topic/com.arm.doc.ddi0210c/index.html"]here[/url].Also, you may want to find the user guide for the specific chip that you have, as vendors will typically add their own peripherals and features to the processor. Because these elements are not added by ARM, you won't find their details on the ARM documentation page.Thanks,Jacob