DS785UM1
10-41
Copyright 2007 Cirrus Logic
DMA Controller
EP93xx User’s Guide
1
0
1
0
10
to indicate that the external device has requested service.
The STATUS register is written by software to clear the
DREQS status bit, thus causing the DMA to ignore the
request.
For level-sensitive DREQ mode, do not attempt to clear
the DREQS status bit, as the request will keep coming
from the external device. The hardware ensures that a
write to the STATUS register has no effect when in level-
sensitive mode.
BCRx
Address:
BCR0: Channel Base A 0x0010 - Read/Write
BCR1: Channel Base A 0x0014 - Read/Write
Definition:
The Channel Bytes Count Register contains the number of bytes yet to be
transferred for a given block of data in a M2M transfer. Only the lower 16 bits
are valid.
Bit Descriptions:
RSVD:
Reserved. Unknown During Read.
BCRx:
x = “0” or “1” representing the double buffer per channel.
The BCR register must be loaded with the number of byte
transfers to occur. It decrements on the successful
completion of the address transfer during the write-to-
memory state of the M2M transfer. At least 1 of the BCRx
registers must be programmed to a non-zero value before
the ENABLE bit and the START bit (in the case of
software-trigger M2M mode) are set in the Control register.
Writing to a BCRx register causes a next buffer update,
that is, only the BCR of the buffer descriptor has to be
written to in order to use that buffer since the SAR_BASEx
and DAR_BASEx registers do not have to be continuously
updated.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RSVD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BCRx
Summary of Contents for EP93 Series
Page 28: ...P 6 DS785UM1 Copyright 2007 Cirrus Logic Preface EP93xx User s Guide PP P ...
Page 162: ...5 36 DS785UM1 Copyright 2007 Cirrus Logic System Controller EP93xx User s Guide 55 5 ...
Page 576: ...15 18 DS785UM1 Copyright 2007 Cirrus Logic UART2 EP93xx User s Guide 1515 15 ...
Page 634: ...17 38 DS785UM1 Copyright 2007 Cirrus Logic IrDA EP93xx User s Guide 1717 17 ...
Page 648: ...19 6 DS785UM1 Copyright 2007 Cirrus Logic Watchdog Timer EP93xx User s Guide 1919 19 ...
Page 688: ...21 32 DS785UM1 Copyright 2007 Cirrus Logic I2S Controller EP93xx User s Guide 2121 21 ...
Page 790: ...27 20 DS785UM1 Copyright 2007 Cirrus Logic IDE Interface EP93xx User s Guide 2727 27 ...
Page 808: ...28 18 DS785UM1 Copyright 2007 Cirrus Logic GPIO Interface EP93xx User s Guide 2828 28 ...