COBHAM GR712RC - 26.4.1 Data formatting

GR712RC-UM, Jun 2017, Version 2.9 189 www.cobham.com/gaisler
GR712RC
26.4.1 Data formatting
When in the decode state, each candidate codeblock is decoded in single error correction mode as
described hereafter.
Figure 79. Direct Memory Access
START
INIT
init rx_w_ptr (lower bits)
fifo 50% full ?
CHECKOVERFLOW
temp1 = rx_w_ptr
temp2 = rx_w_ptr +
temp3 = rx_r_ptr
temp2 >=
WRITE
burst of writes @ temp1
temp1 >=
RESET
temp1 = start addr+x
INCREMENT
temp1 = temp1+x
UPDATE
rx_w_ptr = temp1
set overflow-flag
temp3-offset ?
end addr?
# bytes received
N
Y
N
NY
Y
START
INIT
init rx_r_ptr & rx_w_ptr (ASR register)
CHECKWAIT
temp1 = rx_w_ptr
temp2 = rx_r_ptr
temp1 = temp2 ?
READ
read @ temp2
temp2 =
RESET
temp2 = start addr+y
INCREMENT
temp2 = temp2+y
TBD ms
end addr ?
N
NY
fifo 100% full ?
CHANNEL RESET
Y
all data read ?
N
Y
YN
HARDWARE WRITE SOFTWARE READ
Legend:
rx_w_ptr Write pointer
rx_r_ptr Read pointer