MicroBlaze Processor Reference Guide www.xilinx.com 57
UG081 (v6.0) June 1, 2006 1-800-255-7778
Xilinx CacheLink (XCL) Interface Description
CacheLink Transactions
All individual CacheLink accesses follow the FSL FIFO based transaction protocol:
Access information is encoded over the FSL data and control signals (e.g.
and ICACHE_FSL_IN_Control)
Information is sent (stored) by raising the write enable signal (e.g.
The sender is only allowed to write if the full signal from the receiver is inactive (e.g.
DCACHE_FSL_OUT_Full = 0). The full signal is not used by the instruction cache
Information is received (loaded) by raising the read signal (e.g.
The receiver is only allowed to read as long as the sender signals that new data exists
(e.g. ICACHE_FSL_IN_Exists = 1).
For details on the generic FSL protocol please refer to the “Fast Simplex Link (FSL) bus”
data sheet (DS449).
DCACHE_FSL_IN_Read Read signal to D-side
return read data FSL
std_logic output
DCACHE_FSL_IN_Data Read data from D-side
return read data FSL
(0 to 31)
DCACHE_FSL_IN_Control FSL control bit from D-
side return read data FSL
std_logic input
DCACHE_FSL_IN_Exists More read data exists in
D-side return FSL
std_logic input
DCACHE_FSL_OUT_Clk Clock output to D-side
read access FSL
std_logic; output
DCACHE_FSL_OUT_Write Write new cache miss
access request to D-side
read access FSL
std_logic; output
DCACHE_FSL_OUT_Data Cache miss access (read
address or write address
+ write data + byte write
enable) to D-side read
access FSL
(0 to 31)
DCACHE_FSL_OUT_Control FSL control-bit to D-side
read access FSL. Used
with address bits [30 to
31] for read/write and
byte enable encoding.
std_logic; output
DCACHE_FSL_OUT_Full FSL access buffer for D-
side read accesses is full
std_logic; input
Table 2-8: MicroBlaze Cache Link signals
Signal Name Description VHDL Type Direction