U
SING
THE
L
ATTICE
M
ICO
S
YSTEM
S
OFTWARE
:
Creating the Microprocessor Platform in MSB
22
LatticeMico32 Hardware Developer User Guide
Slave-Side Fixed Arbitration
The slave-side fixed arbitration scheme
enables multiple masters to access multiple slaves at the same time. In this
scheme, each multi-master slave has one arbiter. Arbitration between
different master ports occurs at the slave side. This scheme enables multiple
master ports to obtain access to multiple slave ports, as long as they do not
try to access the same slave at the same time.
Each master port connected to the arbiter has priority of access to the slave
ports. In the case of simultaneous access requests by multiple master ports,
the highest-priority master port is granted access to the slave. Master ports
Figure 7: Connections Made by MSB for Shared-Bus Arbitration
LM32 CPU (Master)
Instruction
port
Data port
Shared bus
arbiter
Peripheral 4
Peripheral 2
Peripheral 3
Peripheral 1
Figure 8: Connections Made by MSB for Slave-Side Arbitration
LM32 CPU (Master)
Instruction
port
Data port
Peripheral 4
Peripheral 2
Peripheral 3
Peripheral 1
Arbiter 2
Arbiter 1
