TS68302MAB Atmel Corporation, TS68302MAB Datasheet - Page 34

• Manufacturer Part Number: TS68302MAB
• Description: 16-bit Communication Controller, 16-20 MHz
• Manufacturer: Atmel Corporation

Functional
Description
Figure 27. Buffer Memory Structure
34
DUAL-PORT RAM (1152 BYTES)
TS68302
SMC1 DESCRIPTOR
SMC2 DESCRIPTOR
SCP DESCRIPTOR
TX DATA BUFFER
DESCRIPTORS
DESCRIPTORS
DESCRIPTORS
SCC1 BUFFER
SCC2 BUFFER
SCC3 BUFFER
TABLE
TABLE
TABLE
The TS68302 uses a microprocessor architecture which has peripheral devices con-
nected to the system bus through a dual-port memory. Various parameters, counters,
and all memory buffer descriptor tables reside in the dual-port RAM. The receive and
transmit data buffer may be located in this on-chip RAM or in the off-chip system RAM
(see Figure 29). Six DMA channels are dedicated to the six serial ports (receive and
transmit for each of the three SCC channels). If an SCC channel’s data is programmed
to be located in the external RAM, the CP main controller (RISC processor) will program
the corresponding DMA channel to perform the required accesses. If the data resides in
the on-chip dual-port RAM, then the CP main controller accesses the RAM with one
clock cycle access and no arbitration delays.
The buffer memory structure of the TS68302 can be configured by the software to
closely match I/O channel requirements. The interrupt structure is also programmable to
relieve the on-chip 68000/68008 core from bit manipulation functions for peripherals,
allowing the processor to perform application software or protocol processing.
In some cases, the interface to equipment or proprietary networks may require the use
of standard control and data signals. For these signals, the TS68302 can be pro-
grammed to use the NMSI mode. This mode is available for one, two, or all three SCC
ports; remaining ports may then use one of the multiplexed interface modes: IDL, GCI,
or PCM.
D
E
R
TX BUFFER DESCRIPTORS (8)
RX BUFFER DESCRIPTORS (8)
FRAME STATUS
FRAME STATUS
DATA POINTER
DATA POINTER
DATA LENGTH
DATA COUT
DATA COUT
RX DATA
TX DATA
DATA
EXTERNAL MEMORY
RX DATA BUFFER
TX DATA BUFFER
2117A–HIREL–11/02