Link Port Communication Protocol - Analog Devices ADSP-TS101 TigerSHARC Hardware Reference Manual

Link Port Communication Protocol

The DMA channel of any port not being used for boot must be cleared
and reinitialized. If the DMA channel is not deactivated, the link inter-
rupt mechanism does not work. The link may be reinitialized as well.
!
If both links that are connected to each other start transmitting at
the same time, unexpected results may occur (up to protocol dead-
lock). The system designer must initialize the system in such a way
that one of the links transmits first.
Link Port Communication Protocol
The link port communicates through an 8-bit data bus, using three con-
trol signals. There is a set of link pins for each link port. In the link pin
names, the "x" stands for the link port—0, 1, 2, or 3. The control signal
pins are:
•
LxCLKIN
when the link receives, and as an acknowledge when the link
transmits.
•
LxCLKOUT
when the link transmits, and as an acknowledge when the link
receives.
•
LxDAT7–0
The data is transmitted or received one byte every
Transfers are of quad-words. The transfer begins from byte 0.
• – Link direction indication
LxDIR
The
LxDIR
or receiving. It is used when the links are buffered.
The link port protocol includes a Transfer Acknowledge and an optional
Connectivity Check for each quad-word transferred. Errors resulting from
these handshakes are described in "Error Detection Mechanisms" on
page 8-17.
8-8
– The pin is an input that functions as a clock
LxCLKIN
– The pin is an output that functions as a clock
LxCLKOUT
– Data bus input and output
pin is an output that indicates if the link is transmitting
ADSP-TS101 TigerSHARC Processor
Hardware Reference
edge.
LxCLK