25
IDT72V51233/72V51243/72V51253 3.3V, MULTI-QUEUE FLOW-CONTROL DEVICES
(4 QUEUES) 18 BIT WIDE CONFIGURATION 589,824, 1,179,648 and 2,359,296 bits
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
the devices connected in expansion. In expansion mode one device will be
set as the Master, MAST input tied HIGH, all other devices will have MAST
tied LOW. The master device is the first device to take control of the PAEn bus
and place the PAE status of its queues onto the bus on the first rising edge of
RCLK after the MRS input goes HIGH once a Master Reset is complete. The
ESYNC (PAE sync pulse) output of the first device (master device), will be HIGH
for one cycle of RCLK indicating that it is has control of the PAEn bus for that
cycle.
The device also passes a “token” onto the next device in the chain, the next
device assuming control of the PAEn bus on the next RCLK cycle. This token
passing is done via the EXO outputs and EXI inputs of the devices (“PAEn
Expansion Out” and “PAEn Expansion In”). The EXO output of the first device
connecting to the EXI input of the second device in the chain, the EXO of the
second device connects to the EXI of the third device and so on. The EXO of
the final device in a chain connects to the EXI of the first device, so that once the
PAEn bus has cycled through all devices control is again passed to the first
device. The EXO output of a device will be HIGH for the RCLK cycle it has control
of the bus.
Please refer to Figure 25, PAEn Bus – Polled Mode for timing information.
