User`s manual

Chip Errata
DSP56305 Digital Signal Processor
Mask: 0F13S
DSP56305 Errata  1996 - 2002 Motorola pg. 8 /ng/12/20/02
ES46
Cont.
(Errata #46 continued)
For systems using the HI32 and DMA interface, in which the host
processor stores the exact number (N) of words to receive or transmit, the
following workarounds can be used:
Transfers from the HI32 to the DSP; DMA reads from DRXR:
a. The host processor writes N words to HTXR with the DMA channel
working in mode 5 (TM = 101) and programmed to receive N words
(DCO initial value equals N –1) with the DMA interrupt enabled.
b. After the DMA has read the N words, it enters the ISR, which disables
the DMA, updates the pointers, and re-enables the DMA.
Note: This is based on Workaround #2 above.
Transfers from the DSP to the HI32; DMA writes to DTXS:
a. The host processor is required to read N words with the DMA chan-
nel working in mode 5 (TM =101) and programmed to transmit N + 6
words (DCO initial value equals N + 5) with the DMA interrupt en-
abled.
b. By the time the host processors completes reading of the N words
from HRXS, the DMA has filled the FIFO and entered the DMA
interrupt. The DMA ISR should disable the DMA, update the
pointers, and generate a software reset to the HI32 by writing 000 to
HM in the DCTR. After this is complete (i.e., HACT in DSR is cleared),
the ISR can re-enable the HI32 and the DMA controller.
Transfers from the DSP to the HI32; DMA writes to DTXM:
a. The host processor is required to read N words with the DMA chan-
nel working in mode 5 (TM =101) and programmed to transmit N + 8
words (DCO initial value equals N +7) with the DMA interrupt en-
abled.
b. By the time the host processors completes reading of the N words
from HRXS, the DMA has filled the FIFO and entered the DMA
interrupt. The DMA ISR should disable the DMA, update the
pointers, and generate a software reset to the HI32 by writing 000 to
HM in the DCTR. After this is complete (i.e., HACT in DSR is cleared),
the ISR can re-enable the HI32 and the DMA controller.
Note: This is the same as a DMA write to DTXS, except for the number
of words for which the DMA is programmed.
0F13S
Errata
Number
Errata Description
Applies
to Mask