Analog Devices adsp-2100 Manual page 235

10 Memory Interface
The ADSP-2171 and ADSP-2181 processors have an additional feature, the
Bus Grant Hung (
multiprocessor system with a minimum number of wasted cycles. The
BGH
pin asserts when the ADSP-21xx is ready to execute an instruction
but is stopped because the external bus is granted to another device. The
other device can release the bus by deasserting bus request. Once the bus
is released, the ADSP-21xx deasserts
external access. Figure 10.22 shows timing for the
CLKOUT
BR
BG
PMS
DMS
BMS
BR
BG
PMS
DMS
BMS
Figure 10.21 Bus Request (with and without external access)
10 – 22
BGH
) output, which lets them operate in a
If no memory access is in progress, BG is
asserted in the cycle after BR is recognized:
If a memory access is in progress, BG is asserted in
the cycle after the access is completed:
BG BGH
and and executes the
BGH
signal.