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GR716-DS-UM, May 2019, Version 1.29
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GR716
31: 4
Conditional Next descriptor pointer address (NEXT_PTR) - Address of the data descriptor in the
descriptor chain which the conditional descriptor is bond to. Cannot be NULL.
3: 1
Conditional descriptor version. This bit field should be set to ’0’ in normal mode and set to ’1’ for
extended mode
0
Conditional descriptor type (DT) - Descriptor type field, ‘0’ for data descriptors, ‘1’ for conditional
descriptors. Must be set to ‘1’ for this type of descriptor.
Table 280.
GRDMAC Conditional descriptor address field (address offset 0x04)
31
6
5
0
COND_ADDR[31:6]
COND_ADDR[5:0] / IRQN
31: 0
Conditional Address (COND_ADDR) - Address of the 32-bit word the core will read for the condi-
tional termination expression matching.
5: 0
IRQ Trigger Line Number (IRQN) - Index of the IRQ_TRIG signal input vector which is used as the
triggering line for triggered conditional descriptors, 0 to 63.
Note:
The register has dual purpose. When DMA is configured for polling all 32 bits are used for address and when
DMA is configured for trigger events only 6 bits are used. Bits 6 to 31 are ignored for trigger events and should
be regarded as a reserved bit field.
Table 281.
GRDMAC Conditional descriptor control field (address offset 0x08)
31
16 15
4
3
2
1
0
COND_SIZE
COUNTER_RST
AN CT IT EN
31: 16
Conditional descriptor total size (COND_SIZE) - Total size in Bytes of the data that will be fetched
from the bond data descriptor each time the conditional termination expression matches to true.
15: 4
Conditional descriptor counter reset value (COUNTER_RST) - Reset value of the conditional
counter timer that is executed before every polling or triggering. The unit is number of clock cycles
and the purpose is to provide a timer between polling requests onto the AMBA AHB bus with
enough clock cycles in order not to clog the bus.
3
Conditional descriptor AHB Master Interface Number (AN) - If set to ‘0’, the descriptor’s transfer
will be performed by the main AHB Master Interface (AHBM0). If set to ‘1’, the descriptor’s trans-
fer will be performed by the second AHB Master Interface (AHBM1).
2
Conditional descriptor Termination Condition type (CT) - If the conditional descriptor is of type
“polling”, this bits specifies which type of termination condition is used. If ‘0’, the termination con-
dition is of type 0 as specified in this paragraph. If ‘1’, the termination condition is of type 1.
1
Conditional Descriptor Irq Trigger (IT) - If set to ‘1’, the conditional descriptor will wait for the
input interrupt line to go high before executing the bond data descriptor. The selected interrupt line is
the one indexed by IRQN in the IRQ_TRIG signal input vector. This bit enables triggering behavior
of conditional descriptors. If this bit is set to ‘0’, normal polling behavior with termination condition
is enabled.
0
Conditional descriptor Enable (EN) - If set to one, the descriptor will be enabled, otherwise it will be
skipped and the next descriptor fetched from memory.
Table 282.
GRDMAC Conditional descriptor mask field (address offset 0x0C)
31
0
COND_MASK
Table 279.
GRDMAC Conditional descriptor next_descriptor field (address offset 0x00)