lf4415 LOGIC Devices Inc., lf4415 Datasheet - Page 21

• Manufacturer Part Number: lf4415
• Description: Video Memory / Fifo
• Manufacturer: LOGIC Devices Inc.

Register 10, 11, 12
Programmable
Empty Flag 1
Definition
Register 13, 14, 15
Programmable
Full Flag 0
Definition
LOGIC Devices Incorporated
Configuration Register Definitions
Register 10 [7:2] Reserved [LOAD as ‘000000’ IF MODIFYING REG 10]
Register 10,11,12 = EMPTY_THRESH_1[17:0] - PE1 Programmable threshold for the Partially
Empty Flag behavior
EmptyThresh1 is a 18bit constant used to define the emptiness threshold for the PE1 flag. The default is
1/80th of the total memory space of channel 0. In single channel and cascade modes, this threshold is
ignored. In dual channel mode, this threshold applies to channel 1’s PE flag.
Register 10= EMPTY_THRESH_1[17:16] (DEFAULT= 00)
5:0=EMPTY_THRESH_1[17:16] Most significant 2 bits of the 18bit EmptyThresh1
Register 11 = EMPTY_THRESH_1[15:8] (DEFAULT= 00000000)
7:0=EMPTY_THRESH_1[15:8]
Register 12 = EMPTY_THRESH_1[7:0] (DEFAULT= 00000000)
7:0=EMPTY_THRESH_1[7:0]
Register 13 [7:6] Reserved [LOAD AS ‘00’ IF MODIFYING REG 13]
Register 13,14,15 = FULL_THRESH_0[21:0] - PF0 Programmable threshold for the Partially Full
Flag behavior
FullThresh0 is a 22bit constant used to define the fullness threshold for the PF0 flag. The default is
79/80th of the total memory space in single channel mode. In single channel and cascade modes, this
threshold applies. In dual channel mode this threshold only applies to channel 0’s PF flag.
Register 13= FULL_THRESH_0 [21:16] (DEFAULT= 00000)
5:0=FULL_THRESH_0 [21:16]
Register 14 = FULL_THRESH_0 [15:8] (DEFAULT= 00000000)
7:0=FULL_THRESH_0 [15:8]
Register 15 = FULL_THRESH_0 [7:0] (DEFAULT= 00000000)
7:0=FULL_THRESH_0 [7:0]
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Middle byte of the 18bit EmptyThresh1
Least significant byte of the 18bit EmptyThresh1
Most significant 6 bits of the 22bit FullThresh0
Middle byte of the 22bit FullThresh0
Least significant byte of the 22bit FullThresh0
21
PRELIMINARY
High Performance Memory Product
Video Memory / FIFO
January 23, 2008 LDS-44xx-A
FRAME
MEMORY
LF4460
LF4430
LF4415