C515C Datasheet, PDF (41/69 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C515C
CAN Controller
The on-chip CAN controller is the functional heart which provides all resources that are required to
run the standard CAN protocol (11-bit identifiers) as well as the extended CAN protocol (29-bit
identifiers). It provides a sophisticated object layer to relieve the CPU of as much overhead as
possible when controlling many different message objects (up to 15). This includes bus arbitration,
resending of garbled messages, error handling, interrupt generation, etc. In order to implement the
physical layer, external components have to be connected to the C515C.
The internal bus interface connects the on-chip CAN controller to the internal bus of the
microcontroller. The registers and data locations of the CAN interface are mapped to a specific 256
byte wide address range of the external data memory area (F700H to F7FFH) and can be accessed
using MOVX instructions. Figure 17 shows a block diagram of the on-chip CAN controller.
Figure 17
CAN Controller Block Diagram
Semiconductor Group
41
1997-07-01