Echelon Series 6000 Chip databook - Manual (Page 30)

Register Size (Bits) Contents
BP 16 Address of 256-Byte Base Page
DSP 8 Data Stack Pointer within Base Page
RSP 8 Return Stack Pointer within Base Page
TOS 8 Top of Data Stack, ALU Input
Processor 1 is the MAC layer processor that handles layers 1 and 2 of the seven-layer
LonTalk ® protocol, which includes driving the communications subsystem hardware and
running the media access control algorithm. The MAC processor communicates with the
NET processor using network buffers located in shared RAM memory, as shown in Figure 5.
Processor 2 is the network processor that implements layers 3 through 6 of the LonTalk
protocol. The NET processor handles network variable processing, addressing, transaction
processing, authentication, background diagnostics, software timers, network management,
and routing functions. The NET processor uses network buffers in shared memory to
communicate with the MAC processor, and application buffers to communicate with the APP
processor. These buffers are also located in shared memory (RAM). Access to the shared
memory is mediated with hardware semaphores to resolve contention when updating shared
data.
Processor 3 is the application processor. The APP processor executes the user-written code,
together with the system services called by user code.
MAC
Processor
Network
Processor
Application
Processor
Interrupt
Processor
Shared
Network Buffers Application Buffers
Communications
Port
Input/Output
Figure 5. Processor Shared Memory Allocation
18 Hardware Resources